Some fabrics that are great for clothing are a different weight or texture than typical quilting fabric. Depending on the quilt, this may or may not be a problem. For example denim and t-shirts are both used in quilts and in clothing quite successfully, yet don't match with typical quilting fabric. In general I find it a personal preference sort of thing, since I don't believe in the quilt police! LOL! I use all sorts of fabric for whatever I want to, just realize that certain ones (satin, corduroy, upholstry fabric, etc) are going to require slightly different techniques to be sure they perform the way I want them to.