Define function before tolerance
A tolerance is meaningful only in relation to fit, motion, sealing, alignment, load or another functional need. Applying the tightest value everywhere increases cost without necessarily improving performance.
Align datums and measurement
Datum structure, feature access, part condition and measurement equipment can change the reported result. Agree the measurement method for critical characteristics before production.
Plan evidence with the order
State whether the project requires first-article results, dimensional reports, material records, surface-finish data or other documentation. Sampling frequency should reflect risk, volume and customer requirements.
Control revisions
The quotation, process plan and inspection program should all reference the same drawing revision. Changes require documented review of cost, timing and validation impact.