I don't think fanfic readers realize just how rewarding it is getting comments on older fics, or fics I've long completed. I think there's just this idea that "oh, the author won't read it anyway" or "they probably won't respond because of how long ago they made it"
Personally, when I see a comment on a work I've already completed, at first I'm surprised, but then I get extremely excited! Like people are still reading this shit??? And they care enough to talk about it???
Again, personally, I'm still writing fics and updating them, but I check ALL of my comments. It doesn't matter how old it is, if you have a question or wanna breakdown a decision I made however long ago, I will respond!
I know I'm not the only one who feels this way, so this is just a friendly reminder to not be afraid to comment on older fics! Or fics you've reread a million times over! We love that, we appreciate it immensely, and it does make our day!