What is better? Cancel account or change email?

[Lunar]

So, after doing a bit of research, a friend of mine has implemented safer surfing practices.

For accounts with iops started before the safer practices were implemented, would it be better to cancel the account and start a new one or just change the email registered with? I wonder in either case if the info, i.e. old email, actually gets scrubbed from the iop's database.

What about this forum? If my friend changes his email will the old one get scrubbed?

Thanks