Hey Vavilon, nice illustration! Yes, it's a very good idea, you check and everything is reset, a reset button, anything but something. In another post, I was just wondering if there was automatic pruning for discussion / conversation. The answer is no, because it may concern several people, which I understand very well in his answer Alex thought "space" but I also thought about the notifications.
In your example, it's 233, it could just as well be 2000, 5000 or 10.000, just now on my site dolphin I still had the case of a member whose registration date was 2011 and who suddenly wakes up, I have cases like that every day.
I know you're going to tell me, delete inactive accounts. No, I refuse to delete old accounts because I consider that an account is never dead IF his email address responds, so I only delete the notifications bounce and every day that passes me, in every case is my phylosophy.
I also do not show the dates of last connection and so people receive mail all the time, that's also why one day or another, so they come back on.
On dolphin it does not pose any problems it is cleaned and the guy does not end up with 50,000 notifications, yes, over 7 years is plausible, even see worse for a woman.