2 days
I’m using aliases differently. I let every mail through that is send to my domain. Then at websites I register with an alias per website and only create an alias in my Fastmail once the alias is starting to send spam so the mails will be removed whenever an email is send to that alias.
Yeah that can happen. Usually its just some webshop that got hacked and leaked my email alias. Than it is easy: block all emails to that alias and create a new account whenever I shop there again.
It has happened twice this year that my email was leaked from a company that I could not just remove my account or block all mails. In those cases I changed my email address on their website to a new alias.