One of the important elements of strategic management is to establish resource levels over the long run—capacity planning. More specifically, managers are faced with the need to determine resource levels that are sufficient to meet corporate objectives and remain competitive; and, yet, not excessive. This research has explored the relationship between ten different availability levels of resources in a constrained, multiple resource environment and their impact on project completion times and promise date performance measures. It also evaluated four finite scheduling heuristics which use a finite scheduling system and are used to estimate and, then, meet a project's completion date in the dynamic, multi-project environment. As a part of the discussion we examine the tradeoff between project completion times and resource availability levels. This research has found that (1) three of the four tested finite scheduling heuristics can produce/meet very good promise dates; (2)-resources do not need to be provided in quantities that exceed 160% of system requirements; (3) when resources are provided at the 130% or greater level, all four heuristics perform equally well with regard to completion times, and complete projects at less than one and a half times a project's critical path time; and (4) when resources are greatly constrained (110% to 130%) the effects are significant and the choice of heuristic is very important.