Scope creep in custom apparel happens the same way it happens in construction and software: small changes, each individually reasonable, that cumulatively double your cost and timeline.

"Can we just add one more color?" In screen printing, each color is a separate screen. Adding a color can add $50–100 in setup plus per-unit cost. In DTG, adding color to an existing design is free if the art is already approved but costs a reprint run if production has started.

"Can we just change the size from M to L?" If production has started, this is a reprint. If the garment is cut, it's a restocking fee and a new order. "Can we add 5 more": same piece price but a new setup time cost.

The protection: write down the exact order before production starts. Quantity, sizes, garment style, color, design version (include version number), placement, and deadline. Get your supplier to confirm in writing before production starts.

If you need to change something after production has started: ask what it will cost before approving. Not "just make the change": "what does that change cost and how does it affect my timeline?"

This isn't adversarial. It's clear communication that protects both parties.