You can check if your data has leaked in one of the many leaks on the "Have I been Pwned" site. On the site you can enter your email or phone (including international phone code) to check if your data such as your password has leaked to any of the hacked databases, including the leaked 500 million on Facebook.
It is a good practice to never use an old password, but always a new and possibly random one, such as https://passwordsgenerator.net/ or another similar service to generate a random password. Wondering why not use an old password? Because if it has expired, it can be used to steal your email and everything related to it. It is recommended that you change your password to change your password with a brand new one once a year (this is the minimum level of security).
If you do not want to remember your passwords, use Password Managers. So you only need to remember one password to open the Password Manager. There are many Password Managers, choose the one that is best for you. For example LastPass, DashLane, 1Password and others.