Safety is very important, but remember that just because you are using a safety device doesn't mean that it is protecting you -- It must be used correctly. Respirators are an example of this. An easy way to tell if you have a good fit with your respirator is to lightly place your hands over both cartridge inlets to block them off and then inhale. The face mask should suck in. If it does not, you are getting air in from a poor fit and remember the air is going to take the path of least resistance. This is where the Respo-Rator and powered air respirators are nice as they do not require fitting.
Don't forget that the hazard is still present when the grinder is shut off. There is still stuff floating around in the air that you need to protect yourself from as well.
Hearing protection is another area that a good fit is required in order to get the protection that the manfacturer claims.
If you use a glass platen, it is best to have a "shelf" for it to rest on so if it comes loose, it cannot get between your belt and wheels and explode.
I run my belts rather tight on my KMG and found that if a belt breaks, the tension spring can shoot out like a rocket. I have my spring safety wired to the frame to keep it in place during a belt break.
Brian