OPINION EN BANC
BOUDIN, Chief Judge.Manuel Vega-Santiago appealed from his conviction on one count of armed carjacking, 18 U.S.C. § 2119(1) (2000), and two counts of related weapons offenses, id. §§ 924(c)(1)(A), 922(k), asserting various trial errors. He also appealed from his prison sentence of 240 months, which represented an upward variance from the sentencing guidelines range of 177 to 191 months that would otherwise have applied to him.
A panel of this court affirmed Vega’s conviction and sentence, remanding only to correct a discrepancy between the written and oral judgments. United States v. Vega-Santiago, 519 F.3d 14, 2007 WL 3171337 (1st Cir.2007). We granted rehearing en banc to consider the panel’s ruling that the district judge must provide “notice” to litigants before imposing a sentence outside the guideline range — a requirement that the panel found satisfied in this case.
The facts in detail can be found in the panel opinion. Vega-Santiago, 519 F.3d at 18-20, 2007 WL 3171337, at *1-*3. Pertinently, here the district judge chose — pursuant to the sentencing regime established by the Supreme Court, United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005); see also United States v. Jimenez-Beltre, 440 F.3d 514 (1st Cir. 2006) (en banc)—to impose a sentence above the range applicable under the sentencing guidelines. He did so after weighing the sentencing factors outlined in 18 U.S.C. § 3553(a)—in particular, the nature of the offense and the background of the offender. Neither the presentence report nor the government’s pre-hearing submissions had suggested varying from the guidelines.
The question before us is whether a district court, before sua sponte imposing a sentence outside the recommended guideline range, must automatically provide advance notice to the parties of its intent to do so and its contemplated reasoning. The circuit courts being divided,1 the Supreme Court is now likely to decide the issue, United States v. Irizarry, 458 F.3d 1208, 1212 (11th Cir.2006), cert. granted, — U.S.-, 128 S.Ct. 828, 169 L.Ed.2d 625 (2008) (No. 06-7517), but until it does, district judges in this circuit are entitled to guidance on an issue potentially present in every sentencing. Our answer is that notice is sometimes, but not always, required.
Much of the dispute among our sister circuits has concerned the applicability of *3Federal Rule of Criminal Procedure 32(h). The rule provides that:
Before the court may depart from the applicable sentencing range on a ground not identified for departure either in the presentence report or in a party’s prehearing submission, the court must give the parties reasonable notice that it is contemplating such a departure. The notice must specify any ground on which the court is contemplating a departure.
Prior to Booker, the guidelines were mandatory save for “departures” that could be allowed by the district judge only in accordance with rules imposed both by the governing statute and the guidelines themselves. The term “departures” refers specifically to just such deviations. Rule 32(h) speaks explicitly of “departures,” a term with a precise legal meaning. U.S.S.G. § 1B1.1 cmt. n. 1(E) (2007); United States v. Diaz-Villafane, 874 F.2d 43, 49 (1st Cir.1989). Departures continue to be available after Booker and it is to them that Rule 32(h) is addressed.
Booker has created new latitude for district judges by permitting them to treat the guidelines as advisory and, after calculating the guideline sentence (including any departure), to impose a different sentence based on the broader criteria identified in the statute. Such deviations have been variously labeled — “variance” is one common term — but they are not “departures” either in technical terminology or in common parlance. On its face, Rule 32(h) cannot apply of its own force to variances, a distinct concept developed after the rule was promulgated.
It is far from clear whether the drafters of the rule would have included variances within the rule if they had then existed, but it does not matter: a formal rule can be changed through the statutorily prescribed rulemaking process, which includes congressional oversight of proposed changes, but it cannot be rewritten ad hoc by an individual judge or panel. “[A] legislature says in a statute what it means and means in a statute what it says there.” Conn. Nat’l Bank v. Germain, 503 U.S. 249, 253-54, 112 S.Ct. 1146, 117 L.Ed.2d 391 (1992). So, too, with formally adopted rules.
The more difficult question is whether the reasoning that prompted Burns v. United States, 501 U.S. 129, 111 S.Ct. 2182, 115 L.Ed.2d 123 (1991) — the decision that Rule 32(h) codified — should be extended without qualification ho this new context to establish a judicially created rule requiring automatic advance notice for variances. The Supreme Court could, and might in the end, choose to do so. But this would be an expansion of Bums ’ holding, which was specifically directed to departures.2
The Court in Bums held that courts may not depart from the guidelines if neither the presentence report nor the prehearing submissions of the parties had requested such a departure, unless reasonable notice is provided. That requirement was said to be implicit in the demands of a federal rule giving parties the right to comment on “matters relating to the appropriate sentence.”3 Without notice, the *4Court reasoned, counsel will be unprepared to comment meaningfully on grounds for departure proposed by the judge, resulting in a lack of adversarial testing. Burns, 501 U.S. at 135, 111 S.Ct. 2182.
There are competing arguments as to whether and how far Bums and its rationales bear on variances; and the Supreme Court will answer those questions in due course. But our view is that, in this different context, adopting a mechanical rule would be a mistake: it would not respond to the realities of a system in which judges are afforded much broader discretion than in the recent past, it would reinforce guideline sentencing, and it would considerably complicate and prolong the sentencing process.
A bright-line advance notice requirement for potential departures fit sensibly within the mandatory guideline regime in place when Bums was decided. The guidelines provided for departures, and articulated specific grounds upon which they can (and cannot) be premised. E.g., U.S.S.G. §§ 4A1.3, 5K1.1 through 2.23. Although in theory the possible grounds for departure were unbounded, in practice they functioned almost as a set of auxiliary guidelines. See Koon v. United States, 518 U.S. 81, 95-96, 116 S.Ct. 2035, 135 L.Ed.2d 392 (1996) (“The court must bear in mind the Commission’s expectation that departures based on grounds not mentioned in the Guidelines will be ‘highly infrequent.’ ”).
Thus, departures presented a finite number of specific, discrete (and often binary) determinations that would govern departures and thus the ultimate sentence. It made sense to advise the parties in advance of any proposed departure so as allow them to dispute the facts critical to the departure and to assist the court on pertinent legal questions.4 The premised facts were reviewable for clear error; the legal rulings, fully reviewable. 18 U.S.C. § 3742(e). In short, departures looked much like the customary fare of adversarial litigation.
Under Booker, Rita v. United States, -U.S.-, 127 S.Ct. 2456, 168 L.Ed.2d 203 (2007), and now Gall v. United States, — U.S.-, 128 S.Ct. 586, 169 L.Ed.2d 445 (2007), the sentencing inquiry, after calculating the guideline range, is far more broad, open-ended and discretionary. Under Booker, the district court must independently consider the statutory sentencing factors, 18 U.S.C. § 3553(a), which are phrased in very general terms {e.g., “the nature and circumstances of the offense”; the need for the sentence “to reflect the seriousness of the offense”). A variant sentence may then be imposed based on a complex of factors whose interplay and precise weight cannot even be precisely described.
The district judge draws on information from the trial, the pre-sentence report and the parties’ commentary, the defendant’s allocution, victims’ statements, letters, its own review of these materials before the sentencing hearing and whatever is added during the hearing. Throughout the hearing, the judge may well be revising his views depending on what is presented and how counsel respond to questions. This is a fluid and dynamic process and the court itself may not know until the end whether a variance will be adopted, let alone on what grounds.
*5Yet in order to provide advance notice of any value, a district court would have to advise not only that a variance is possible but also the ground and reasoning behind it before he has even heard the full presentation. This is very different than the identification in advance of a particular ground of departure that may or may not be invoked. “[Requiring advance notice of ‘any ground’ ... would undoubtedly prove to be unworkable.” United States v. Vampire Nation, 451 F.3d 189, 197 (3d Cir.2006).
Further, a mechanical requirement of such notice is unnecessary. In the normal case a competent lawyer — and for incompetence other remedies are available — will anticipate most of what might occur at the sentencing hearing — based on the trial, the pre-sentence report, the exchanges of the parties concerning the report, and the preparation of mitigation evidence. Garden variety considerations of culpability, criminal history, likelihood of re-offense, seriousness of the crime, nature of the conduct and so forth should not generally come as a surprise to trial lawyers who have prepared for sentencing.
Were a mechanical notice rule imposed, some judges would shy away from imposing non-guideline sentences that the parties had not proposed in advance, increasing the “gravitational pull” of the guidelines, United States v. Trujillo-Terrazas, 405 F.3d 814, 819 (10th Cir.2005), and compromising the greater freedom sought by Booker and Rita. See, e.g., Rita, 127 S.Ct. at 2465 (holding that a district judge “does not enjoy the benefit of a legal presumption that the Guidelines sentence should apply”). Alternatively, the judge would often have to employ a burdensome two-stage regime, explaining at the end of the first hearing his proposed sentence and then conducting a follow-up hearing based on such notice.
The preferable solution is thus not a mechanical rule mandating formal notice in every case where the judge may conceivably vary from the guidelines. Rather, when proposing to adopt a variant sentence relying on some ground or factor that would unfairly surprise competent and reasonably prepared counsel, a judge must either provide advance notice or, on request, grant a continuance in order to accommodate a reasonable desire for more evidence or further research. No formal rule is required for us to adopt such a prudential policy as a matter of precedent.
In practice such cases of unfair surprise, probably rare, are not that hard to identify; and this case is not one of them. Here, the district judge relied primarily on three particular details of the crime — that it involved the invasion of a home, death threats and a near-miss firing of a gun — and that Vega had been previously arrested (but not convicted) on charges of violent crime. The details of the crime were well known to counsel; and Vega had admitted his prior “brushes with the law” which were noted in the presentence report.5
Defense counsel may not have anticipated that the district judge would rely upon those particular facts to impose an above-guideline sentence, but having that knowledge in advance would not have made any obvious difference. The facts themselves were familiar and undisputed, so there is no concern here that counsel might have *6been able, with notice, to challenge them. And nowhere else in the law is the judge required to explain his reasoning before counsel have argued to him.
In granting rehearing en banc we invited supplemental briefing not only on the panel’s automatic notice requirement but on whether there was unfair surprise in this case. Defense counsel have added new arguments to those earlier presented to the panel. But we agree with the panel’s original view that unfair surprise has not been established. At sentencing defense counsel had ample opportunity and incentive, without any advance notice of a possible variance, to make the same arguments now offered to us.
First, Vega submits that mitigating evidence about his family circumstances could have been offered. But mitigating evidence would have been relevant to sentencing with or without a variance from the guideline range. The principal factor cited, the death of Vega’s father shortly before the crime, was readily detectable by counsel and potentially useful to argue for a lower sentence within or (under Booker) below the guideline range.
Next, Vega contends that a carjacking that involves invading a home is no worse, for purposes of the section 3553(a) factors, than an ordinary carjacking. We fail to see how further notice was necessary in order to prepare that argument about the seriousness of the offense facts — a typical sentencing consideration. Comparing and contrasting a defendant’s particular crime to its “heartland” prototype is always relevant. That the judge might think that a home invasion carried an extra sense of menace is hardly a surprise.
Finally, Vega says that the death threat and firing of the gun were already taken into account by the guidelines, and that with more notice, defense counsel would have been prepared to point that out. But a factor that is worked into the guideline calculus may still be considered by a district judge in the section 3553(a) analysis. See, e.g., United States v. Scherrer, 444 F.3d 91, 93-94 (1st Cir.2006) (en banc), cert. denied, — U.S.-, 127 S.Ct. 927, 166 L.Ed.2d 714 (2007). Anyway Vega’s counsel did emphasize — without requiring any special notice — that the enhancements provided in the guidelines were sufficient. The district judge simply did not agree.
Parts I, II, 111(A), and 111(C) of the panel opinion are reinstated; Vega’s conviction and sentence are affirmed; and the case is remanded for correction of the written judgment.
It is so ordered.
. Five circuits have held that notice is required. United States v. Anati, 457 F.3d 233, 237 (2d Cir.2006); United States v. Davenport, 445 F.3d 366, 371 (4th Cir.2006); United States v. Cousins, 469 F.3d 572, 580 (6th Cir.2006); United States v. Evans-Martinez, 448 F.3d 1163, 1164 (9th Cir.2006); United States v. Atencio, 476 F.3d 1099, 1104 (10th Cir.2007).
Four have concluded to the contrary. United States v. Vampire Nation, 451 F.3d 189, 195 (3d Cir.2006); United States v. Mejia-Huerta, 480 F.3d 713, 722 (5th Cir.2007), petition for cert. filed, 75 U.S.L.W. 3585 (Apr. 18, 2007) (No. 06-1381); United States v. Long Soldier, 431 F.3d 1120, 1122 (8th Cir. 2005); United States v. Irizarry, 458 F.3d 1208, 1212 (11th Cir.2006), cert. granted, — U.S. -, 128 S.Ct. 828, 169 L.Ed.2d 625 (2008) (No. 06-7517); see also United States v. Walker, 447 F.3d 999, 1006 (7th Cir.2006) (holding notice no longer required even for traditional departures).
. The government, which has an obvious interest in obtaining notice of contemplated downward variances, has reversed the position it took before the panel and now insists that Rule 32(h) does apply. But it imbues the notice requirement with such flexibility as to whether and when notice must be given that its position is ultimately quite different from Vega's.
. This rule remains in force, Fed.R.Crim.P. 32(i)(I)(C), but reflects only a general policy on the right to comment and does not specify at all whether and when notice of anything must be given.
. Departures often required the judge to analyze not only the guidelines, but also the policy statements of the Commission (which were binding, Stinson v. United States, 508 U.S. 36, 113 S.Ct. 1913, 123 L.Ed.2d 598 (1993)), and the circuit law relating to appropriate and inappropriate grounds.
. Vega points out that the district judge agreed to strike that portion of the PSR at the start of the sentencing hearing. But, as the judge explained when delivering the sentence, it was removed only because Vega's counsel was concerned that the Bureau of Prisons would use it to "jack up his security level.” The truth of the admission was not contested.