Every 6 months, unless you suspect a breach (change immediately then).
Absolutely not. Facebook uses salted hashes, meaning even Facebook employees cannot see your password. facebook password
No. One account, one password. However, you can set up App Passwords (a feature for older apps that don’t support 2FA, now deprecated). Conclusion: Guard Your Facebook Password Like Your House Key Your Facebook password is a master key to your digital life. Treat it with the same seriousness as your bank PIN. A strong, unique password, combined with two-factor authentication and awareness of phishing scams, will keep your memories, messages, and identity safe. Every 6 months, unless you suspect a breach
Moderately safe. Chrome's password manager is decent, but a dedicated password manager is better. Conclusion: Guard Your Facebook Password Like Your House
You cannot. You must first recover the password using "Forgot password?" then log out all devices.