I memorize my passwords and reuse them to a large extent. Strength of the password is actually a lot less important than the website's security and the value of the account.

* relatively weak/old passwords for sites I don't care about and would lose nothing if they were compromised (vast majority)

* a couple relatively strong passwords for the 5-6 sites I don't want compromised, but wouldn't have huge consequences and could be email recoverable.

* unique strong passwords for a couple vital services such as email account.

The re-use depends somewhat on how much I trust the site's security. Also I cycle occasionally by introducing new passwords at the "top" and moving those passwords "down" to less important sites.