Watch-list sweep - a few questions

Hey, people! Sorry for being inactive for a while, things have been going over my head lately. School, mostly.

Anyway, I did a two-hour sweep of my whole watch-list today and noticed that I watched quite a lot of people who hadn't been active since 2012-2013-ish. I know my original intention was "But if they come back, I'll be notified!" but it's getting to the point where most people I watch are inactive and my inbox are literally dead - also because a lot of them decided to move account and decided to try over, I'm still watching a lot of dead accounts (I don't get the reason to leave one account and go to another but still leave the other one in tact. If I switched account, I would deactive the other one...). I watch people for either personal reasons or because their art really inspire me or encourage me to try harder. With that said, I also had quite a lot of people I watched because they came around and were like "Hey, cool gallery, watch me?" and of course, like the little people-pleaser I've been for a long time, I did. Even if I had no reason at all to do so.

Now, I know I don't have that many watchers but I treasure each and single one of them (even if I know quite a big part of them are inactive or deactivated - dA really needs to do something about that, it's getting on my nerves that you can keep watching an account that is deactivated).

So yeah, I went from watching about 400 people to almost 250, which is still a lot of people but much more manageable than before. (Also unwatched a lot of groups because why pretend I'm part of it when I'm not even interested?)

Now to the tings I'm wondering:
Does anyone else ever do a watch-list sweep? And if so, do you keep watching people who haven't posted anything within the last two years or so?
What's your criteria for watching someone? Do they need to update every week or doesn't it matter as long the content meets your expectations?
What's your opinion about switching to a new account but leaving the old one in tact? Have you done that? And if so, did you leave the other one in tact?

I hope to get to post a lot more once I've graduated school. Won't be more than two months.