It's my understanding that voting power recovers at a rate of 20% per day. Even at 90+% I'm still only giving out a penny per upvote. I've been being a little stingy with my upvotes lately to try to keep my voting power up. I generally go through my feed and upvote followers/following posts first, then look for new posts from people I haven't seen before to upvote, then upvote comments if I have enough voting power left and am burnt out on reading through posts.