[¶ 1.] This was a case of admitted liability. The jury was required to determine damages. Lori Ann Smith (Smith) appeals the award of damages to Warren Michael Jurgensen (Jurgensen) in the amount of $310,000. Smith alleges that based on the evidence presented, the trial court erred in not allowing her to introduce evidence that Jurgensen’s financial condition was similar before and after the accident. Smith further alleges the trial court erred in not allowing her to assert a mitigation of damages defense. We affirm.
FACTS
[¶2.] On January 23, 1996, Jurgensen was involved in a car accident with Smith. The accident occurred when Smith failed to stop at a red light. As a result of the accident, Jurgensen sustained serious physical injuries to his neck, back and shoulder and incurred substantial economic losses. Smith admitted liability in her answer and at trial. Thus, the only issue at trial was damages.
[¶ 3.] At the time of the accident, Jur-gensen was employed by Electric Construction Company (Electric Construction) as a licensed journeyman electrician. His pay rate at the time of the accident was $16.26 per hour as a journeyman and $19.67 per hour as a foreman. Jurgen-sen’s annual income prior to the accident was approximately $41,000 per year plus benefits.
[¶ 4.] On the date of the accident, Jur-gensen was on his way to work at the First National Bank Building where he was supervising a small crew cleaning and fixing light fixtures. When he was about half a block from an intersection, the traffic light turned green. Jurgensen proceeded through the intersection where his vehicle was broadsided by Smith’s vehicle. Jur-gensen was taken to an emergency room where he was treated for a head injury. He was discharged with instructions to follow-up with his physician if his condition did not improve.
[¶ 6.] Jurgensen’s condition did not improve so he sought chiropractic treatment on January 29. Dr. Mark Hagen (Hagen) examined Jurgensen and took x-rays. The x-rays revealed Jurgensen’s back and neck had suffered severe trauma as a result of the accident and were out of alignment. The trauma had also caused the ligaments and nerves to break apart which resulted in a soft tissue injury.
[¶ 6.] The injuries to Jurgensen’s neck and back prevented him from working from January 29 to April 4. During these months, Jurgensen underwent physical therapy designed to heal and strengthen the muscles in his back and neck. Although he returned to work on April 15, his pain persisted and he was forced to take another leave of absence from work. At this point, Jurgensen was referred to Dr. Myung Cho (Cho), a physiatrist specializing in the field of physical medicine and rehabilitation.
[¶ 7.] Cho found that Jurgensen’s pain was consistent with injuries sustained in an automobile accident. Cho treated Jur-gensen- from August to December and prescribed trigger point injections and physical therapy designed to improve Jur-gensen’s muscle strength. Initially, the injections and therapy helped relieve the *441pain, but it reoccurred as Jurgensen’s work duties increased. In December, Cho released Jurgensen to return to work on a trial basis with a thirty pound lifting restriction. Within a week of returning to work, the pain returned to Jurgensen’s back and neck and he was again forced to leave his job with Electric Construction. At that point, Cho ordered a Functional Capacities Evaluation (FCE).
[¶ 8.] An FCE is a comprehensive assessment of a patient’s ability to deal with: weight; lifting or carrying; and'the type of position they are able to tolerate, e.g. kneeling, standing, walking, or reaching above the head. Cho reviewed the FCE and concluded that Jurgensen was capable of performing medium level work. Cho then ordered a job site evaluation.
[¶ 9.] Stan Kulzer (Kulzer), an occupational therapist with Avera McKennan Hospital, went to Electric Construction and performed the job site evaluation. After visiting the job site, Kulzer concluded Jurgensen was not able to continue working as an electrician due to the injuries he received as a result of the car accident. In addition, Cho determined that a combination of lifting more than 25 pounds and reaching overhead prevented Jurgensen from returning to his job as a journeyman electrician.
[¶ 10.] On December 14, Jurgensen quit his job with Electric Construction. Jur-gensen had sought a lighter duty position with Electric Construction, but no such positions were available. Jurgensen contacted his union and learned that Crescent Electric had an opening for an electrical estimator. He applied for that job, albeit for lower pay, but was not hired because he lacked the necessary experience and training with computers.
[¶ 11.] Faced with an inability to work as an electrician and growing financial trouble, Jurgensen sought vocational counseling. He filled out applications, took aptitude tests and went to classes designed to direct him toward a new career. During the course of this counseling, Jurgensen interviewed with Rick Ostrander (Ostran-der), a vocational rehabilitation specialist. Ostrander concluded that by transferring Jurgensen’s skills to a less physical occupation, such as pharmacy, he could return to the standard of living to which he was accustomed.
[¶ 12.] In 1997, Jurgensen enrolled' in pre-pharmacy classes at South Dakota State University in Brookings, South Dakota. Testimony by Ostrander and Dr. Ralph Brown, a professor and economist at the University of South Dakota, indicated Jurgensen would lose more money by taking a lower paying substitute job than he would by returning to school for six years to become a licensed pharmacist. The evidence presented' indicated Jurgensen would lose a total of $294,000 from the time of his accident to the time of his graduation with a pharmacy degree. In addition, it was undisputed that Jurgensen incurred medical bills in the amount of $15,141.09.
[¶ 13.] On March 10, 1999, after hearing all of the evidence and testimony, the jury returned a verdict in favor of Jurgensen in the’ amount of $310,000. The court entered judgment on the verdict on March 11.
[¶ 14.] Smith raises the following issues on appeal:
Whether the trial court abused its discretion in refusing to allow Smith to introduce evidence that Jurgensen received financial benefits from collateral sources.
Whether the trial court abused its discretion in refusing to grant Smith a jury instruction on mitigation of damages.
ANALYSIS
[¶ 15.] Did the trial court abuse its discretion in refusing to allow Smith to introduce evidence that Jurgensen received financial benefits from collateral sources?
*442[¶ 16.] Smith argues that because references to Jurgensen’s financial condition were made by both Jurgensen and his attorney, she should have been allowed to introduce evidence that Jurgensen received benefits from collateral sources. This argument is unpersuasive.
[¶ 17.] It is well settled under South Dakota law that “ ‘[t]otal or partial compensation received by an injured party from a collateral source, wholly independent of the wrongdoer, does not operate to reduce the damages recoverable from the wrongdoer.’ ” Moore v. Kluthe & Lane Ins. Agency, Inc., 89 S.D. 419, 484, 234 N.W.2d 260, 269 (1975)(quoting Swift & Company v. Gutierez, 76 Idaho 82, 277 P.2d 559, 561 (1954)). Furthermore, a plaintiffs collateral source of income “cannot be inquired into as part of a defendant’s case, because of the danger that the jury may be inclined to ... reduce a damage award, when it learns that plaintiffs loss is entirely or partially covered.” Moses v. Union Pacific R.R., 64 F.3d 413, 416 (8th Cir.1995). This rule of law rests on the premise that it is more just that a windfall benefit an injured party as opposed to a tort feasor. See Hamilton v. Slover, 440 S.W.2d 947, 958 (Mo.l969)(overruled on other grounds by Stover v. Patrick, 459 S.W.2d 393 (Mo.1970)).
[¶ 18.] The trial court ruled that Jurgensen’s testimony did not open the door for Smith to introduce evidence of collateral sources. A trial court’s eviden-tiary rulings are presumed correct and will not be reversed unless there is a clear abuse of discretion. See Opp v. Nieuwsma, 458 N.W.2d 352, 357 (S.D.1990); Magbuhat v. Kovarik, 382 N.W.2d 43, 46 (S.D.1986). An abuse of discretion has been defined as a decision that is not justified by, and is clearly against reason and evidence. Dakota Cheese, Inc. v. Taylor, 525 N.W.2d 713, 715 (S.D.1995). This Court will not reverse a decision if it “ ‘believe[s] a judicial mind, in view of the law and the circumstances, could reasonably have reached that conclusion.’ ” See id. (quoting Rosen’s, Inc. v. Juhnke, 513 N.W.2d 575, 576 (S.D.1994)). Moreover, this Court has cautioned that it “must be careful not to substitute [its] reasoning for that of the trial court.” State v. Larson, 512 N.W.2d 732, 736 (S.D.1994).
[¶ 19.] The mere fact that Jurgen-sen’s financial status was introduced is not enough to warrant a finding of abuse of discretion by the trial court. As we noted in Atkins v. Stratmeyer, 1999 SD 131, ¶ 14, 600 N.W.2d 891, 897, “[w]e decline to extend the law to prohibit every single mention of financial status or insurance in cases such as this where it is vital to establish the amount of damages.” Therefore, the trial court’s ruling prohibiting Smith from introducing evidence that Jur-gensen allegedly received funds from collateral sources was reasonable in light of the law and circumstances.
[¶ 20.] Did the trial court err in refusing to give a jury instruction on mitigation of damages?
[¶ 21.] In her second assignment of error, Smith contends that the trial court erred when it refused her proposed jury instruction on mitigation of damages. Of note is the fact that Smith failed to plead the affirmative defense of failure to mitigate damages. In fact, it was not raised until the settlement of instructions. Under South Dakota law, a defendant is required to plead any and all affirmative defenses in the answer to the plaintiffs complaint. See SDCL 15-6-8(c). Mitigation of damages is an affirmative defense. See Kowing v. Williams, 75 S.D. 454, 459, 67 N.W.2d 780, 783 (1954). This Court could find that the mitigation of damages argument was waived by Smith under our holding in Farmers Cooperative El. Co. of Revillo v. Johnson, 90 S.D. 36, 237 N.W.2d 671 (1976).
[¶ 22.] Smith’s argument would fail even if this court were to allow her to amend her pleadings. It is well settled *443that the court need only instruct the jury on issues supported by competent evidence in the record. See Bauman v. Auch, 539 N.W.2d 320, 323 (S.D.1995). Additionally, to obtain a reversal for failure to give a requested instruction, an appellant has the burden of proving that the jury might and probably would have returned a different verdict had the proposed instruction been given. See Chambers v. Dakotah Charter, Inc., 488 N.W.2d 63, 64 (S.D.1992). Smith has not met that burden. The record is replete with evidence that Jurgensen took reasonable steps to improve his condition, including enrolling in a six-year pharmacy program at South Dakota State University. There is little, if any, evidence in the record to support a jury instruction on mitigation of damages. We find that the instructions given at trial correctly apprised the jury of the applicable law and the requisite quantum of proof.
[¶ 23.] Affirmed.
[¶ 24.] KONENKAMP, Justice, concurs.
[¶25.] MILLER, Chief Justice, concurs specially. [¶ 26.] AMUNDSON, and GILBERT-SON, Justices, dissent. [¶ 27.] TRIMBLE, Circuit Judge, for SABERS, Justice, disqualified.