‘Measure twice, cut once’ is a phrase I originally heard watching woodworking and home improvement shows like ‘This Old House’. But the same adage applies to quilting.
To save yourself a lot of heartache (not to mention fabric), never, Never, NEVER assume a quilting pattern is 100% correct! EVERYONE makes mistakes, and especially in the case of FREE patterns you find online, there are often errors. Sometimes it’s a simple typo, other times the math has not been checked carefully and you may find yourself short of fabric or having cut some pieces the wrong size.