Definitely hold it up to the light - if you can see through it, you'll know that it's not very tightly woven and will shrink a lot. I've noticed differences even in the same fabric line, because I think they may use different mills for production. Also, some dyes are more expensive so in order to keep the entire line at the same price per yard, they may cut corners on the quality of the yarns and the denseness of the weave. I have all sorts of fabrics in my stash - good stuff, mediocre stuff and bad stuff. All of it gets used.