A few I know to keep. The rest I figure if they are important they will return.
Exactly. There is no harm in periodically wiping out all your cookies. Just login again to your favorite sites and provide your password. Besides, it gets you to remember your password. Too many people rely on the passwords being remembered by "the system" until one day you need to manually enter it but have to scramble to find out where you wrote it down. Another thing you can do is to use multiple browsers, some with private security and allowing nothing to be kept, and delete and reload them as needed. Others can allow cookies and only be used for the trusted sites. Too many people only use a single browser for everything they do. You want security, you need to stay on top of it just like guarding your home.