[jolmg]

Use an address with the domain of your paid email provider for site sign-ups. The email provider is going to have more to lose than you if control over the domain is lost.

Use a custom domain for person-to-person communications. This allows you to change email providers later without having to make sure all your contacts know you've changed your address, by just informing the sites you're signed up at.

The risk from losing your personal domain then is just someone impersonating you to your personal contacts (if they know them) or site users if you're hosting anything at that domain.