Same username? That's assuming it's still available. If it isn't ? Then you have to remember a one-off username. Also, I do not use the same password for all web sites. That's the most basic security FAIL. If someone figures out your password, then all your accounts are compromised. This is the worst security advice ever. I'm sorry - but you know this is true.

Yes - I also do the dummy email forward. I agree about not giving random sites your google account. So create a dummy google account.