1) Background: This study employs a simulation-based approach, adapting the waterfall model, to provide estimates for projects and individual phase completion times. Additionally, it pinpoints potential efficiency issues stemming from suboptimal resource levels. It further demonstrates ways to identify resource levels that create bottlenecks and result in idle resources. (2) Methods: We implement our software development lifecycle simulation using SimPy, a discrete-event simulation framework written in Python. Our model is executed on 100 projects of varying sizes over three stages. The first, pre-optimization, provides insight based on the initial set of resources. This is followed by the optimization stage, which serves to identify the optimal number of resources to eliminate bottlenecks and minimize idle time. The third stage, post-optimization, evaluates the resource optimized model. (3) Results: The analysis of the simulation-generated data reveals the presence of resource bottlenecks during the pre-optimization stage, particularly in the implementation phase. These dissipate after optimization. (4) Conclusions: The findings emphasize the advantage of using simulation as a safe and effective way to experiment and plan for software development projects. Such simulations also allow those managing software development projects to make accurate, evidence-based projections as to phase and project completion times and identify optimal resource levels and their interplay. In particular, understanding the tradeoffs between experiencing delayed completion times and procuring additional resources to alleviate any bottlenecks.