Unfortunately upvoting every comment can quickly drain one's voting power. I recommend authors upvote insightful and well thought out comments. And if you get in a discussion upvote just one of that users comments.
I sometimes use an upvote as the "end" of a conversation and upvote the last comment made by a user. Sometimes if I find the comment useful or interesting I'll look at a user's post and upvote it instead.
Of course if you're not concerned with curation rewards.. upvote away!
I doing that most of the time.
Follow, Followup, FollowBack
Oh! Poor me , I helping everyone and wasted all my SP
UPVOTES on them. I get Bugger all.Well said @patrice
Do author really know who upvoting them?
I do. I takes every single UPVOTES seriously !!!