For my club night b'shells, I cut out a strip of scrap lexan and make two holes in it at the same spots as the front bodyposts would be for that b'shell. I then nut and bolt the scrap piece of lexan to the front of the b'shell. If you make the holes on the b'shell slightly bigger than they should be, all the cracks and splits will appear on the scrap piece of lexan that you bolted on. Once that piece is totally shot, replace it, and your b'shell should last a little longer than normal!
Hope that helps,
Chris.