For example, email clients generally allow you to use multiple accounts at the same time. Configure your client to read emails from both accounts at the same time, and any time an important email arrives at the legacy account try to update the sender.

(I mean, I'm sure that xkcd.com/1172 applies, but still this seems like an odd thing to be blocked by.)

I'd rather begrudgingly keep taking advantage of Google's spam filter over adopting the added workflow branch that is perceivably likely to trail me for another decade-plus.