There you stand in the fabric store, that giant display of bias tapes and bindings in front of you, its shiny cellophane packages glinting in their neat, color coordinated rows. Single fold, double fold, blanket, quilt. Geeze! What's what? Do you just throw a dart and hope for the best? No! You bring your Sew4Home Cheat Sheet with you and get exactly what you really need.
It's something you might not have noticed until you started sewing. The pattern on a printed fabric is not always lined up with the grain of the fabric (the up-and-down and side-to-side direction of the thread -- the warp and weft). Back when all patterns were woven into fabrics this wasn't a problem because the weave was the pattern. But now with most patterns being printed onto the fabric after it's woven, the 'registration' can be off a little. Or a lot. And that can wreak havoc with your sewing.