Use the "passwords" feature to check if one of yours is compromised. If it shows up, never ever reuse those credentials. They'll be baked into thousands of botnets etc. and be forevermore part of automated break-in attempts until one randomly succeeds.
Protip for the room: Use a password manager with a unique password for every service. Then when one leaks, it only affects that singular service, not large swaths of your digital life.
Also, length is most of what matters. A full length sentence in lowercase with easy to type finger/key flow for pw manager master, and don't know a single other password. Can someone correct me if I'm wrong?
As always, the most secure password is the least convenient and accessible. It's a trade off, but you want fewer dictionary words and patterns overall. Preferably with a physical component for the master password.
Longer is better...giggitty.