Many people use the same password across multiple sites because remembering different passwords for each service can be challenging, but this practice poses a significant security risk if one account is compromised. To mitigate this risk, using a password manager is recommended, as it helps track passwords securely. There are two main types: web-based and local programs, with the latter being favored by experts like Johan Edholm from Detectify, due to the reduced risk of cloud-based hacking. Edholm advises against relying on browser autofill functions for passwords due to potential security vulnerabilities and suggests using password managers like KeePass or Password Safe, which store passwords in a secure vault accessible via a master password. It's also important to back up the password manager on an external drive for added security.