I've always had multiple email addresses, right now I have 6:

• One "private": let's say it's the main one, used for everything except for the things I use the other ones for.
• One "dev": for my dev related accounts: GitHub, Dev.to, DigitalOcean, Namecheap, that kind of things.
• Two for work: as a consultant I have an address at my company and one at the client's premises.
• A Gmail address: for Google stuff only.
• A "dirty" address: I don't really use it, but when I need to create an account I'm not sure to keep, I use this address, it allows me to keep the main one clean.

... and I'll probably have a 7th one soon enough (for freelancing, my dev one wont do and I'd like to keep work-related stuff outside the private one).

But I'm starting to think it's too much... hence the question:

How many email addresses do you use? What for?