Originally posted by Jed
Use it ALL the time. It doesn't hurt, and it might do a world of good in some situations. Helps to eliminate contrast loss due to flare, helps to eliminate visible internal lens reflections (also known as flare confusingly enough), helps protect the front of the lens from bumps. But don't bother trying to put it on when you need it and not otherwise. Just use it all the time. That's not a curt example, that's good advice.