Many websites don't seem to have mandatory session expiry. I have Firefox set to clear everything except cookies and site preferences when I close my browser, a

Many websites don't seem to have mandatory session expiry. I have Firefox set to clear everything except cookies and site preferences when I close my browser, and then set cookies to "until I quit Firefox", with exceptions for sites I want to stay logged in to (reddit, HN, few other non-critical but frequently visited sites) set to "allow". Self-destructing cookies to purge cookies from closed tabs after a timeout is also a useful extension.