This is an appeal from an order modifying an award of alimony and child support. At issue is whether an increase in the non-custodial parent’s ability to pay can, by itself, constitute a material change in circumstances sufficient to justify an increase in support. We conclude that it can and reverse the order of the trial court.
I.
In March 1982, after twenty years of marriage, the parties divorced. Pursuant to the divorce decree, Mr. Graham was *356ordered to pay Mrs. Graham alimony of $250 per week and child support of $375 per week ($125 for each of their three children); in addition, he was to pay half the monthly mortgage on the marital home and all private school tuition for the children. At about the time the judgment of absolute divorce was entered, Mr. Graham signed a new contract with his employer which provided for significant salary increases.2 Mr. Graham had been earning approximately $100,000 in salary in 1981; under the new contract, his salary was to be raised to $185,000 in 1982; $210,000 in 1983; $230,000 in 1984; and $255,000 in 1985. In August 1982, after negotiations between the parties about increasing support payments in light of these salary increases had broken down, Mrs. Graham filed a Motion to Enforce Agreement or in the Alternative for Increased Alimony and Child Support.
On July 27, 1984, after a three-day evi-dentiary hearing, the trial court issued a Memorandum Opinion and Order in which it held, inter alia, that an increase in the non-custodial parent’s income, no matter how great, was, by itself, an insufficient basis upon which to modify a support order. Relying on Sheridan v. Sheridan, 267 A.2d 343 (D.C.1970), the trial judge stated that in order to prove a “material change in circumstances” sufficient to justify an increase in support, Mrs: Graham was required to demonstrate that the needs of herself and her children had increased since the original support order was entered; only after this threshold showing was made would Mr. Graham’s increased ability to pay be taken into account. Nonetheless, the trial court found that there had been a modest increase in the needs of Mrs. Graham and the children and that Mr. Graham had the financial resources to contribute toward meeting those needs. The court thus increased Mr. Graham’s child support obligation $15 per week per child to $140 per week per child. In addition, the court ordered that the alimony paid to Mrs. Graham be increased from $250 to $350 per week; however, as Mrs. Graham was at the time attending law school part-time and was expected to complete her studies in the spring of 1986, the court ordered that the alimony be decreased to $200 per week beginning in September 1986. Mrs. Graham was also awarded $1,000 in attorney’s fees.3
II.
Mrs. Graham, supported by ami-cus, asserts that the trial court applied an incorrect legal standard in modifying the original support order and thus unfairly limited the amount of the increase. She contends that an increase in the non-custodial parent’s ability to pay can, by itself, provide a proper basis for an increase in support, beyond or without any proven increase in the needs of the children or the other spouse. We agree.4
*357An original support order may be modified only upon a showing that there has been a material change in the circumstances of the parties.5 Hamilton v. Hamilton, supra note 5, 247 A.2d at 422. In Hamilton, we stated that a material change in circumstances can be “a change which affects either the [parent’s] ability to pay or the needs of the minor children,” id. at 422-23 (emphasis added), and we have reiterated this disjunctive standard in several subsequent decisions. See, e.g., Burnette v. Void, 509 A.2d 606, 608 (D.C.1986); Wright v. Wright, 386 A.2d 1191, 1195 (D.C.1978); Tennyson v. Tennyson, supra note 5, 381 A.2d at 266.6
Nonetheless, the trial court was correct in noting that there is language in Sheridan, which suggests that the Hamilton standard is limited to eases in which the non-custodial parent’s ability to pay decreases and further suggests that where the parent’s resources increase, that only the second prong of the test, the increased needs of the children, is a proper basis for modification. Sheridan, supra, 267 A.2d at 346-47. As we later observed in Tennyson, however, these statements were merely dicta, as there was no evidence in Sheridan that the non-custodial parent’s income had in fact increased. Tennyson, supra, 381 A.2d at 266 n. 3. Moreover, as we went on to explain in Tennyson, the statements in Sheridan “appear[ ] overcome by ... subsequent legislative mandate.” Id. D.C.Code § 16-916(a) (1981) requires courts to consider both parents as potential sources of support, and “[t]o ignore a change, occasioned by increase in the [noncustodial parent’s] income, in the relative abilities of the parents to support their child would seem inconsistent with this mandate.” Tennyson, supra, 381 A.2d at 266 n. 3. Thus, given the subsequent development of the law, we consider the language in Sheridan to be a mere aberration and, as dicta, not controlling of our decision in this case.
Having put the dicta in Sheridan aside, we cannot find that the procedure followed by the trial court comported with the standard for modification set forth in Hamilton. Hamilton and its progeny make clear that a material change in either the parent’s income or in the needs of the children and the other spouse may be the basis for modification of the support order. See Hamel v. Hamel, 539 A.2d 195, 199 (D.C.1988). By insisting that there could be no increase in support without a commensurate increase in the needs of Mrs. Graham and the children, the trial court effectively nullified the first prong of this standard.7
*358Nor do we see any reason to apply a different standard where the parent’s income increased and where it is decreased. To adopt such a distinction would mean that children would have to bear the burden of a lowered standard of living when their parent’s income declined but could not share the benefit when that parent’s resources grew — a situation for which we perceive little, if any, sensible justification.8
Furthermore, we think it proper that a material increase in the non-custodial parent’s income can be the basis for an increase in child support. Although spouses may divorce, the children’s legal relationship with both parents continues, and “[t]he children’s station in life should not therefore be fixed forever to their parents’ station in life at the time of the divorce.” Cole v. Cole, 44 Md.App. 435, 409 A.2d 734, 741 (1979). We think it appropriate that a trial court may act to ensure that where there is a material increase in non-custodial parents’ financial resources, that these parents do not increase their own standard of living without also ensuring that their children live as well as they.9
We note finally that the considerations which go into an award of alimony differ somewhat from those which determine child support. In this jurisdiction, parents, for example, have “an unqualified obligation to contribute to the support of their children.” Burnette, supra, 509 A.2d at 608; see also District of Columbia ex rel. W.J.D. v. E.M., 467 A.2d 457, 460 (D.C.1983). By contrast, an award of alimony to a former spouse is a matter left to the discretion of the trial court, Leftwich v. Leftwich, 442 A.2d 139, 142 (D.C.1982), and considerations other than a pure calculus of need and ability to pay (such as the length of marriage and the age of the parties) enter into the initial decision. See McEachnie v. McEachnie, 216 A.2d 169, 170 (D.C.1966). While we may assume that in the vast majority of cases, the relationship between spouses does not not survive after divorce to the same degree that the parent-child relationship does, by law the decree granting alimony, just as does the decree providing for child support, remains open for modification. See D.C.Code § 16-914(a); Tydings v. Tydings, 349 A.2d 462 (D.C.1975). A former spouse seeking an increase in alimony bears the burden of showing that an increase is justified. There must be “a showing of a substantial and material change in the conditions and circumstances of the involved parties since the entry of the decree.” Id. at 463. A modification of alimony “must reflect changed needs or changed financial resources” (as opposed to “offensive” conduct on the part of the receiving spouse). Alibrando v. Alibrando, 375 A.2d 9, 15 *359(D.C.1977). While it may deter marriage, or divorce, or both, to contemplate that the increase in the income of one divorced spouse, standing alone, will provide justification for an increase in support payments to the receiving spouse, a blanket rule precluding spouses from sharing in the increased resources of their former partners would be unacceptable. It may be, for example, that the spouse receiving support has contributed during the marriage so as to be partly or wholly responsible for the other spouse’s subsequent income. Or, at the time of the divorce, there may have been insufficient resources for both spouses to maintain their previous standard of living, and the subsequent increase in the income of the spouse paying support might be used to meet the preexisting, though previously unmet, financial needs of the other spouse. In short, there may be circumstances, though unusual, in which it may be appropriate for the trial court to award increased alimony where only the income of the paying spouse, and not the needs of the receiving spouse, have increased. In any event, this is a matter for the trial court, marshalling the facts pursuant to correct legal standards.
III.
Therefore, we reverse the trial court’s order modifying the prior alimony and support orders and remand for further consideration in light of this opinion. We note that Mrs. Graham also challenges the award of attorney’s fees as inadequate. In view of our reversal of the support modification in this case, we think it proper also to vacate the award of attorney’s fees and remand for further consideration. See Cooper v. Cooper, 472 A.2d 878, 881 (D.C.1984); Owens v. Owens, 427 A.2d 933, 939 (D.C.1981). Finally, as seven years have passed since the entry of the original modification order, we leave it to the trial court’s discretion whether to (1) reopen the record on remand for evidence of further changes in the parties’ financial circumstances since that time or (2) issue a revised order based on the facts as found at the time (and any further findings necessary to the decision) which comports with the standards set forth herein, and then allow the parties to file motions for further modifications as they feel necessary. See Trezevant v. Trezevant, supra, 403 A.2d at 1139.
Accordingly, the order of the trial court is
Reversed and remanded.
. Mr. Graham signed his new employment contract on March 11, 1982, with the terms of the contract made retroactive to January 31, 1982. To place this in chronological context, the trial of the divorce was begun on January 7, 1982, the trial court issued an oral order granting the divorce on January 22, 1982, and the written judgment of absolute divorce was entered on March 23, 1982.
. After the modification order was issued, Mrs. Graham filed a Motion for Reconsideration with the trial court, which was denied as to all matters material here.
. Mrs. Graham makes several other assertions of error in her appeal. Because of our disposition of this initial issue, we are not required to reach Mrs. Graham’s other contentions. In view of the fact that certain of these issues are likely to arise again on remand, however, we offer the following observations as guidance.
First, Mrs. Graham asserts that the trial court made various factual errors in assessing particular expenses, such as home repairs, clothing, etc. These claims are baseless: the trial judge was thorough in reviewing each household expense that had allegedly increased, and each of her conclusions as to these matters is supported by substantial evidence. Second, Mrs. Graham contends that the trial court should have made the increase in support retroactive to August 1982, the date she filed her motion for modification; instead, the court made the increase retroactive to April 7, 1983. This is a matter committed to the sound discretion of the trial court, and the court did not abuse its discretion here. See Trezevant v. Trezevant, 403 A.2d 1134, 1138 (D.C.1979) (“we believe that any reasonable date on or after the filing of the motion may be *357chosen as the effective date of the order, and that this choice should be left to the sound discretion of the trial judge”). Third, Mrs. Graham asserts that it was error for the court to order a prospective decrease in alimony in anticipation of Mrs. Graham completing law school. She is correct in this regard: as we recently reaffirmed in Joel v. Joel, 559 A.2d 769 (D.C.1989), the trial court is required to make any periodic award of alimony a "permanent, fixed amount for an indefinite period of time” and cannot "build in later reductions by speculating about the parties' respective needs and abilities to pay in the future.” Id. at 772. (The trial court does, of course, retain discretion to consider the spouses’ prospective economic conditions in setting the permanent, fixed amount).
Finally, Mrs. Graham asks this court to review the denial of her Rule 60(b) motion concerning the division of marital property. This was the subject of a separate appeal before this court, No. 87-41, and a disposition has since been reached in this matter.
.A motion for modification of support, therefore, is not to be used as a pretense to relitigate the equities of the prior decree. Tennyson v. Tennyson, 381 A.2d 264, 266 (D.C.1977); Hamilton v. Hamilton, 247 A.2d 421, 423 (D.C.1968).
. We also note that, subsequent to the proceedings in this case, the Council of the District of Columbia adopted this as the appropriate standard for modification of child support, and it has been codified at D.C.Code § 30-504 (1988).
. Mr. Graham contends that the trial judge did not, in fact, limit the increase in support to the increase in Mrs. Graham’s and the children’s needs. Rather, he argues, the trial court held that a showing that the children’s needs had increased was simply a threshold requirement; after this threshold was met, Mr. Graham asserts, both his ability to pay and his wife’s and children’s needs could be taken into account. As the trial judge found that the needs threshold was in fact met in this case, Mr. Graham concludes, both factors were fully and independently considered and no harm resulted.
We do not read the court’s order to state this to be the standard it applied. Rather, we under*358stand the trial court, upon finding that the needs of Mrs. Graham and the children had grown, to have looked to Mr. Graham’s increased income solely to determine whether Mr. Graham had the present ability to afford to meet these newly increased needs and never to have viewed Mr. Graham’s increased resources as an independent basis for awarding increased support. See Order of October 11, 1984 (denying Motion for Reconsideration) at 4 (looking to Mr. Graham’s present financial ability to pay increased support and not to his change in circumstances; only Mrs. Graham’s change in circumstances taken into account) and at 4-5 (stating fact that Mr. Graham’s income rose "dramatically” shortly after divorce hearing was "irrelevant” in modification proceedings). We therefore cannot predict what determination the trial court would have reached had it applied the correct standard: given the substantial increase in Mr. Graham’s salary, the court may well have ordered a greater increase in support if it had felt that the award could exceed the increase in the children’s needs.
. There is another form of arbitrariness in this situation as well, in that the children’s well-being comes to depend on the fortuity of which parent’s income increases: in the first case, where the custodial parent’s income rises, the children would almost inevitably benefit, for, as the parent increases the quality of his or her housing and food, for example, it simultaneously increases that of the others in his or her household; in contrast, where the non-custodial parent’s income rises, the children would gain nothing.
. Although not applicable to the present case, the child support guidelines recently enacted by the Council express a similar concern, stating as a basic principle in setting the original support order that "the child should not be living at a standard substantially below that of the noncustodial parent.” D.C.Code § 16 — 916.1(b)(3), 37 D.C.Reg. 3720-21 (1990), enacted in D.C.Law 8-150, § 2, effective July 25, 1990, 37 D.C.Reg. 5138 (1990).