An aggressive timeline can create urgency, but it cannot compensate for unclear engineering requirements. When teams begin sourcing, tooling, or manufacturing before critical decisions are defined, uncertainty does not disappear. It simply moves downstream, where resolving it becomes slower and more expensive.
Ambiguity around materials, tolerances, finishes, functional requirements, expected loads, environmental conditions, or validation criteria forces suppliers and manufacturing teams to make assumptions. Those assumptions may allow work to begin quickly, but they can also produce conflicting quotes, incorrect tooling decisions, failed samples, and repeated engineering changes.
The result is a project that appears fast at the beginning but loses time through clarification and rework. A supplier may quote one interpretation of the requirements while another quotes something entirely different. Tooling may begin before a critical tolerance is finalized. Testing may reveal that different teams were working toward different definitions of acceptable performance.
Clear requirements create the opposite effect. Suppliers can quote accurately, manufacturing teams can choose appropriate processes, quality teams can establish meaningful inspection plans, and engineering decisions can move forward without repeatedly reopening earlier questions.
This does not mean every detail must be frozen before development begins. Iteration is part of product development. What matters is clearly separating what is known, what remains flexible, and what must be resolved before the next commitment is made. A realistic schedule built on clear requirements will often move faster than an aggressive schedule built on assumptions.