For me stash just happens. I only buy for specific projects, and buy the yardage suggested in the pattern. Some patterns have you buy way more than you need. I have several totes full of different size cuts of fabric that I don't know how to use. I keep looking for a scrappy pattern that I like to try to use it, but just haven't found one.
I think the biggest problem is I am so anal and not an artistic cell in my body.