Haveibeenpwned is a great site where you can type in your email and see if it was compromised in an account breach from a website. For example, if you have a MySpace account with your email '*******@123.net' then you would be able to see how many times that your email could have been compromised and how many times has your password been pasted from your account. If your email is found to be breached from a site hack then you should definitely change your password for that email and any accounts that you're using that email for.
