In Penn Elec. Supply Co. v. Billows Elec. Supply Co., 364 Pa. Super. 544, 528 A.2d 643, 645 (Pa. Super. 1987), the Superior Court stated: The general rule in this Commonwealth is that the plaintiff bears the burden of proof as to damages... The determination of damages is a factual question to be decided by the fact-finder.... The fact-finder must assess the testimony, by weighing the evidence and determining its credibility, and by accepting or rejecting the estimates of the damages given by the witnesses.... Although the fact-finder may not render a verdict based on sheer conjecture or guesswork, it may use a measure of speculation in estimating damages.... The fact-finder may make a just and reasonable estimate of the damage based on relevant data, and in such circumstances may act on probable, inferential, as well as direct and positive proof.