If you have pitting along the edge bevel you need to sand it out so that it doesn't interfere with honing. For any other pits, it's up to you to decide whether or not they bother you. Personally, I don't really mind light pitting or discoloration on the blade. I think it adds character.

However, for deep pitting that I want to remove, I find that a belt grinder (at very slow speed) is the most reasonable way to go. Hand sanding would just take too long and would not be worth the effort to me.