The worst that has happened to mine -
1) my grandkids lost theirs in a hurricane - this is before I had thought to label them, and couldn't get any more of the distinctive fabric used in them. I was able to remake one of them.
2) while it was just a quilt top, we had our boat sink, so a bunch of stuff from the boat on the basement floor waiting to be washed, then shortly thereafter, a flood in our basement. The quilt top was on the ironing board, but one corner fell off and touched the moldy stuff from the boat. I tried bleaching the corner, but the color came out of the quilt top, mold still visible. So I ended up appliqueing on corner blocks on the top. That one ended up looking fine.