never.........if the hole is too big, put a small nug at the bottom so shit don't pull through. I always look for this when purchasing a new pipe though, so that I don't have to put a nug at the bottom, only fresh ground herb.
yea always check the bowl hole when buying a new piece....
they have glass screens made of glass they look like little jacks (you remember that game jacks?) that you set down in your bowl, only problem is you have to remember its in there before you dump your ash lol...
I just bought 2oo screens from ebay because i have a metal pipe and if i don't use screens i get a mouth full of ash and mj. my pipe is called a marks a lot pipe it looks like a magic marker.