There are different kinds of people and different kinds of things that they want. There are those that value the comments they get and do their best to check all and there are those that just like that people comment on their posts without them going back to it.
Some like the comments and after they see it they leave and don't do anything to appreciate the time the person has given to read the post and gave something valuable to it. Either an addition or what the post has done for him.
ALL ARE GOOD BUT STICK TO THIS.
You should make sure to give attention to the comments you get cause most times you learn from them or you could add to the what the person wants to know just be replying them. It makes people happy when they give a good comment and their commended for it.
I for one give assurance to people that comment on my posts that will always check them and do what's needed to those that take their time to read and comment on it. Even if my upvote value isn't much I'd always give something.
So you commenting on my post no matter the time you comment. There is an assurance of my vote cause I value comments. Not just comments but quality comments.
I think is good we reply comments it enables those engaging your post to do that over and over again especially when you five them a sound reply