Dimension what you will actually inspect
Mark critical-to-function features. Blanket tight tolerances on every edge inflate cost and stretch lead time without improving assembly fit.
Pick process before you lock cosmetics
As-machined aluminum, Type II/III anodize, molded texture and powder-coated sheet metal read differently under the same lighting. Align finish with process in the RFQ, not after first article.
Design the bridge intentionally
If annual volume will grow, ask for a prototype route that teaches you something transferable to soft or steel tools — CNC masters and urethane batches are useful only when the exit criteria are clear.
Send complete RFQ packages
STEP/IGES + 2D with CTQs, material, volume band, finish and ship-to region. Incomplete packs are why “24-hour quote” promises fail in the wild.