There are four situations in which the rule does not apply, as explained in Evans v. Wilson, 279 Ark. 224, 650 S.W.2d 569 (1983). They are cases in which a collateral source of recovery may be introduced (1) to rebut the plaintiff's testimony that he or she was compelled by financial necessity to return to work prematurely or to forego additional medical care; (2) to show that the plaintiff had attributed his condition to some other cause, such as sickness; (3) to impeach the plaintiff's testimony that he or she had paid his medical expenses himself; (4) to show that the plaintiff had actually continued to work instead of being out of work, as claimed. Id. at 226, 650 S.W.2d at 570. See also HOWARD W. BRILL, ARKANSAS LAW OF DAMAGES § 9-4 (3d. ed 1994). Courts have also allowed evidence of collateral sources when the plaintiff opens the door to his or her financial condition. See Babbitt v. Quik-way Lube & Tire, Inc., 313 Ark. 207, 853 S.W.2d 273 (1993); Younts v. Baldor Electric Co., 310 Ark. 86, 832 S.W.2d 832 (1992).