- mail@firstlast.tld for personal emails directed at me only and written by a human being, i.e. emails that warrant my personal response
- <SomeServiceIsignedUpfor>@firstlast.tld for automated emails from services like Amazon, Facebook, eBay, HN, …. These are usually computer-generated emails that don't warrant a response, so they are merely notifications.
The neat thing about this approach is that:
a) the list of email aliases contains all the services I've signed up for, ever
b) I can easily stop a service from sending me emails by simply deleting the alias. In particular, if an email address leaks to spammers, I simply delete it.
c) I can distinguish between personal and non-personal email and can prioritize accordingly. I look at my personal emails more often than at my non-personal ones.