Quantum meruit exists when “services are provided and accepted under circumstances that would justify an expectation of payment of the reasonable value of those services to the person providing them.” Moran v. Hubbartt, 178 S.W.3d 604, 615 (Mo. Ct. App. 2005). The measure of recovery, if successful, is the reasonable value of the services rendered. At trial, an expert witness is often required to testify about the value of such services.
There is a general presumption that a person expects compensation for their valuable services. However, there is no such presumption if the parties share “familial ties, or are unrelated but have a special relationship from which a reasonable person would believe such services were gratuitously performed.” In re Wyman, 220 S.W.3d 471, 473 (Mo. Ct. App. 2007).
If a defendant desires to use the defense of a family or special relationship, then he or she must plead it as an affirmative defense. Id. Failure to plead it as an affirmative defense may result in waiver of the defense.