I hold my hands up I ask for them to leave a comment but I don't alway upvote I will only upvote comments that I think are justified, example if they leave a comment with "nice post" they wont get my upvote, in fairness I probably upvote one comment per post because I curate and upvote ten other posts a day and it would really hit my steem if I doubled that. Which would take later to recharge. So I try to stick to ten a day, I hope this helps you when you upvote.