I use a program called KeePass (http://keepass.info/) to store my login information for websites. It's a password management tool, which allows for me to use different passwords for each website and keep them all together in a locked file. It also largely automates the login process, so I can access any MSC's site with just a few keystrokes, even though my password might be a 16-character random string of letters and numbers. CTRL-U takes me to the MSC's site, then CTRL-V (usually) logs me in automatically.
Why is this relevant to this thread? KeePass automatically tracks the last time an entry was updated, as well as the last time a site was accessed. That makes it easy for me to tell how long it has been since I last visited a site. I can also put notes in the entry for each MSC. I can even set a password expiration time, which will mark an MSC's entry on my list and let me know at a glance that it's time to log in. When I update my profile, I usually update my password as well, which keeps me active with the MSCs and also keeps my personal data more secure -- which is good practice anyway, given the amount of information we often put into our profiles.