Your browser tends to hold onto information, and over time it could cause problems with logging in or bringing up websites. You may get an error like the one below.
It's always a good idea to clear out the cache, or browser history, and clear cookies on a regular basis.
See the link below for instructions on how to clear your browser cache in Google Chrome from your device.
http://www.refreshyourcache.com/en/chrome-27/
Clearing from Mozilla Firefox
See the link below for instructions on how to clear your browser cache in Mozilla Firefox from your device.
http://www.refreshyourcache.com/en/firefox-20/
See the link below for instructions on how to clear your browser cache in Safari from your device. Remember to make sure that "Passwords" and "Autofill form data" are also checked off.
http://www.refreshyourcache.com/en/safari-5/