As a web developer who constantly deals with domains and emails being transferred, I’d like to set a standard guideline on how one should manage their domains and email in order to maintain autonomy and control over your own material, while eliminating the chances of losing domains through silly administrative mishaps.

ALWAYS keep a public email with hotmail, gmail, yahoo etc., and check it regularly.
Occasionally you may drop a domain name altogether, or stop working for a company, or cut partnership with a company. That means, your old email at john@oldcompany.com …