There have already been several discussions about abandoned questions and more particularly closing them or forcing acceptance to answers, etc. I am curious as to what community consensus might be on how long to give someone to address a request before simply doing it yourself, if possible. Obviously it may not be possible to provide clarification without assumptions or speculation, and it is possible a request may go unnoticed. But many times it is clear a request has either been ignored (later responses or new questions) or the user won't be back any time soon to address it (no recent login or anonymous question).
Let's have an example. In this question clarification was requested, given in comments, and then requested to be edited into the question to clean up and clarify. I agree with this approach, as it helps to inform and educate new users on site protocol and etiquette. In this case the request was clearly seen, since the user visited and provided additional comments after, but never addressed.
The same situation also often arises with 'can you post your comment as an answer'; either asker solved their own problem or someone else did as a comment, which asker saw and thanked as yet another comment, but nobody ever made an actual answer out of it. There are other meta questions that address whether it is appropriate to step in and do this, but not how long to wait before doing so.
I see this with both new users and those with high rep. I understand not everyone has as much time to devote to the site as some do, and there can be a bit of time between logins. Or that an @ wasn't used when it needed to be so the request is never seen, making a 'ping' potentially appropriate. I also understand a desire to be polite - not steal someone else's potential credit/rep (even if you attribute the answer to a comment, your answer is still all that can be upvoted in the rep system), or give them a chance to provide edits.
The closest I've found to a suggested time frame is in Should we move to close old, abandoned questions with not enough detail? which was a couple of days plus checking for last login time (what if they haven't logged in - a week?). Would that apply in cases like this as well?