Strategy for changing your primary email?

Forward $old to $new

Setup a filter in $new email that labels all mail received on the $old address, so you know where you need to update your email address

Keep this until you don't have any more emails coming in with that $old label for ... however long you're comfortable, 6 months, 1 year, forever. Unless there's a reason you need to decommission the $old one, I'd just leave it there

> How would you ensure you haven't missed anything?

This probably isn't of much help now, but adding accounts as they are created to a list, like a password manager, helps to ensure you don't miss any in situations like this.

Quite some time ago, I needed to do a big cleanup of email aliases (I have 500+) and various

My approach was to use IMAP integration with my provider to copy all the emails down to my laptop.

I then used VBA in Outlook to create a list of source email addresses and counts - then I could update places using those emails.

In your case, i'd do something similar.

Analyse your existing emails to get a list of emails by source address (or domain).

Use that list to figure out what places you need to get updated.

Then (per Sydney1's suggestion) - forward old emails to the new address. Preferably tag it somehow so you know that it means there are other places that need to be updated.

I did this a while ago for my own and my wife's email and ten years ago I changed from .nl to .com for the domainname which is effectively the same thing :-) For both it's forward and forget, I changed some services to reflect the mail change, most I didn't bother. After 5 maybe 6 years no e-mail came through the old address anymore. So if you have the time and the couple of $$ to keep it up it's a minor issue, it's self cleaning to a large extent.

Setting up automated forwarding would cover your "ideal" needs. That way you can gradually change your logins and make sure that all email sent to old & new addresses end up in one inbox.

Slowly move all your stuff (user acc around the net) to new domain/email and once 1 year passes with no new emails to your old mailbox, trash it.

if i were moving my primary to a gmail account, i'd setup the "send mail as" thing to receive all the email in your new account, set-up a filter to automatically label it as such, and then set a super strong password w/ 2FA on your previous acct.