I'm not sure, I follow people and things because I enjoy them, I myself am not that great at responding to comments on some of my post, but some of the comments are "Like how do I respond to that?" type of comments.

I have been to some post that had no comments and commented on them, and I have commented on post that have hundreds of comments. Some time I reply to a comment on my comment if it calls for one, but I rarely chase having the "last word" in a comment string.

I guess comments are kind of like votes, time is not an issue of when I vote unless it is past the 7 days, and if it was an exceptional post then I will vote on one of the other not so exceptional post, comments time really does not matter, heck I've commented on post that were over two years old, after all the post if still active will see that they have a comment.

I even on occasion will comment without giving a vote, especially if my vote power is down in the dumps, not often, but sometimes you just can not pass up the comment.