What is the impact at which you need to replace your helmet? I took a small spill earlier in the year. The helmet has a small mark on it. I did not hit hard. Like the helmet and don't want to replace it unless I must/have to. Yes I know it is protecting my head, but being an F4 rider I am sure Randy will have something to say. I have heard of a drop from 3 ft=replace. Mine was more of a slide and not drop. What do you think?