I’ve considered running an email server on my personal domain for some time, but the effort of changing my email hasn’t felt worth it to me, given how many services I’ve signed up for with my current email (a Gmail address). Is anyone aware of any strategies to make this easier? It’d be nice if I could set up forwarding so services would automatically use my new email, but I’m not sure if something like that exists.
Many email service providers give you the option to fetch all emails from a different service not just as a one-time thing, but ongoing. I'm not sure how that could be set up when running your own email server, but I bet there's a way. Even if there isn't, you can set up automatic forwarding in Gmail.
There's a chance forwarding is better than fetching. I once had a Gmail account stolen, and account recovery was locked for some reason, but email forwarding had been set up and I was still able to get all emails the address received.
In case it's relevant, I happen to use Fastmail now and their "mail fetch" feature involves imap.
You can have the Gmail emails be forwarded to your own email server, or have your server fetch them from Gmail, and then migrate bit by bit, the most important accounts first.
Before SPF and the like, it used to be trivial to also send email with a different From address (like your existing Gmail address) from your own server, but that’s not the case anymore.