I typically have one quilt in progress at a time . . .but I always buy fabric as the mood strikes me and there may (or may not) be another quilt percolating in my tiny little mind.
Having a stash makes it easy to take a break between big projects to do a bag or a pillow or whatever; and I am generally a scrappy quilter so I can usually just pick through that stash. I may have to go buy a few yards of some sort of "hold-it-all-together" fabric.
I used to start all kinds of craft projects and leave them half-way through - when I started quilting I promised myself to see it through to the end every time. So far, so good :lol: