I try very hard to answer all my comments, but life sometimes gets in the way. If that happens, I will revisit the comment weeks later to acknowledge it, so they know I saw it.

If I see a comment, I really want to leave a long message back, so I will write a short comment so they know I saw it, but that my brain is "working slow" and I tell them I will be back when I am more awake to answer them more fully.