If you distrust open-source, independent security-audited password managers, you can still use them to generate long, unique, high-entropy passwords. The risk of using low-entropy passwords that you can remember is a far greater risk for most people.

A 10-character password with mixed characters provides only about 26 bits of entropy, which can be cracked in seconds.

In contrast, even just a 12-character password with proper character mixing can achieve 78 bits of entropy, requiring decades to crack even with specialized hardware.

It's not just reused low-entropy passwords being sold on the dark web with the rest of your information that is a threat. With quantum computing just around the corner, the necessity for unique, high-entropy passwords is critical for information security.