I always make a list of what I am shopping for or have been wanting when I go to a show. That helps keep me from what I call passion purchases (stuff I really don't want and never use). As I get older and more experienced it is more difficult to find anything new and/or anything I really want. I'm now busy trying to clear out my (new) sewing room of stuff I don't want and don't use. But the minute I get rid of a tool I find a use for it! Go figure!
I, too, am interested in what Onebyone uses those 18 inch batting squares for. I have seen them for years but have no idea why people buy them.