15 tubs is a lot of fabric! You can't imagine how much until you start sorting through it and trying to figure out where you're going to put it! How do I know? I just bought 11 tubs of fabric and craft stuff off a Craigslist ad.
I've donated almost all of the craft stuff, about 3 tubs worth, and kept most of the fabrics.
My advice is to make sure you have a van to transport it in. Our Dodge Caravan with the foldaway seats was full to the height of ther front seat backs. Also, it might be smart get some measurements of the tubs and figure out if you can fit them in the van. Otherwise, bring lots of the kitchen trash bags so you can kind of smoosh the fabric into the available space.
Good luck.