Ive never really thought about it. I guess if it's worth commenting on and I missed it when it was new I'll comment when I see the post. That being said I don't usually go back to look for older posts.

Doesn't matter but I'm on here most days so not alot slips by. I have a problem.

I'll comment on anything that isn't archived myself.

Depends on content. Current events/news are updated so quickly now that new posts are offered instead of comments to reflect the latest. I'll comment on general interests when I see them, regardless of age.

It really doesn't matter to me. If I see something I missed and I have a comment, I'll comment. I don't necessarily care how old it is in general. But if it were 'very old' ... say a week or more, I'd probably just pass.

Depending on the topic, a couple of weeks seems reasonable.

I post on anything that moves

Under 16 in this state.