Have I Been Pwned?
If you have an email address then this is a great website to check whether it’s safety has been breached.
Basically, you enter your email address and the website “Have I been pwned” by Troy Hunt will check it against the current list of data breaches.
If you’re still not sure you can read more about it on Wikipedia:
I recommend giving it a go, it might remind you of some long forgotten accounts, it did for me!