I have a large stash and work primarily with scrap quilts. I tried keeping useful sizes and decided after about 10 years that ultimately it didn't work for me. I had to store and organize multiple strips of things and even when I went there first, it seemed that I never made a dent in them, the piles just got bigger.
In the last couple of years I've decided I simply don't want to store anything smaller than 6.5" x something bigger than a square. I've given away/used everything smaller than that and now I have one single box for 6.5" strips. I go there first when I'm picking fabrics for my scrap quilts, I can cut off a 2" square but I don't want to fiddle around piecing tiny bits into that square...
It's not something I enjoy but I found a crumb quilter who takes my little bits. It's easy to give away yardage, much harder with the bits. I keep a flat rate postal box by my cutting area and put anything smaller than that 6.5" in there and mail it away periodically. I'm sure a lot of what I send is too big for "crumbs", but she can always cut down and as I said, I can't cut up. She's also happy to take my "strings" those off grain end cuts. I'm rather fussy about when my fabric is stored which is that it has been prewashed, folded ready for cutting, and cut edge straight on grain, I used to keep the raggedy ends but they bother me when I go into that box, so now they go into the crumb box and everyone is happy!