Check and Test Before You Sell

A pattern with one wrong stitch count is a pattern that does not work, and the person who finds out is the customer who paid for it. Testing is how designers catch that first, and it is also the part of the job most of them run on spreadsheets, private Facebook groups and screenshots.

These guides cover the whole check: recounting the arithmetic yourself, what an automated check catches and what only a human tester will, how to run a tester call that gets replies, what testers need from you, and how to keep versions straight once corrections start coming in.