I have experienced this as well. I have never known why they are that way. Mine are very thin at the tips and peel. Could be one of those symptoms that we didn't realize was a side effect of Lupus? Not much help, but I can relate. I try to keep my painted and I use a topcoat called Seche Vite. It's a bit thicker and helps keep the polish on longer. Qtix (spelling might be off) is a nail strengther that I have found helpful as well.