As I have said before, I totally agree with getting your starter motor reconditioned. Worn brushes and armature are what bring things like dirty contacts to light, mainly because of the huge increase in current needed to turn them over. If you don't do it, you'll find yourself like I did, tapping and knocking on the starter motor, frantically trying to get it to go in trying circumstances, usually when a quick getaway is crucial. In our case my one and only time getting caught in a Southerly buster, on a lee shore, in the dark, and with my (original) CQR anchor dragging. (I now have a Sarca, but that's another whole story.) Don't do this to yourself or your family.