Definitely should change mine more than I currently do which is never! I've lost count of the number of times I've had to hit the forgotten pw button on various websites...
I have two master passwords that I should change more often, actually I have not changed them since they were made,and that is for a year now. One of the two passwords is for Roboform where I use virtual keyboard. The other is my Windows Password there I use CTRL+ALT+DELETE before logging on to Windows 7 right before the log on screen, When secure logon is enabled, no other program (such as a virus or spyware) can intercept your user name and password as you enter it. That IS what they say Best Regards
me,like once a year..btw would you guys use password generated by a intewrnet site like http://strongpasswordgenerator.com/