I have 0 in my main inbox (Hotmail) and likely a few hundred (lazy to check) in Gmail. It's forwarding all general emails I get, which I then check read as I use it for video notifications or such. After I build up like 200 or so emails, I just go and sort them into folders or delete. It's mostly from who I follow, and don't like to forget what new videos might be out. Yes I could endlessly refresh a channel / check whenever but it seems silly with 10+ channels at least.
If an email actually doesn't get through, I check my Gmail but other than that I ignore it. Since it's either filtered by Gmail or Hotmail, which can be a pain if it's possibly important. Hotmail is set to exclusive so, I don't see those useless spam emails. Saves a lot of email skimming honestly, with a double filtering to weed out junk.
I don't like reading email in external apps, it's more time to keep opening another app in the end. Since I try to keep a low active app count overall, due to I have to use a rather meh system.