I found only the watched threads I recently clicked into share a notification bell. Your best bet is to just check your watched page itself and scroll it. Anything in there with the little blip next to the title is a thread that has been replied to since your last visit. The blips only go away when you click into those threads. Hope this helped.
Well, I can't be on the site everyday to not miss out on notifications, due to work and real life, me and a lot of people are going to be offline for several days and I know of the method to click "Mark Read" but then that would get rid of old notifications as well, and on top of missing the present notifications I would end up losing the past ones as well.