I clip as I go so I don't have to do a lot of clipping later.and the thread doesn't get under the quilting

I clip as I go, but I tend to have finished quilt tops lingering around for quite some time before I get around to quilting them. Some of them get folded and unfolded several times (either as I'm slowly marking them, or as I'm showing them off) so they get frayed on the back. If it's really bad I'll spend some time trimming off the "hair", but I tend to use a lot of darker fabrics so I can usually get away with just leaving it as-is.