Just the other day I thought of a feature that would be great to have in 1Password...the ability to set expiration dates/times for a password.
I have provided two use-cases where this feature would be extremely relevant.
First, having the ability for 1Password to in-effect remind you to change your password at a set interval would help to increase security and reduce vulnerability. For example, it might be wise to change your password for a banking website every 90 days as a precaution. With this feature, 1Password would remind you to do so. (Part of this feature may already be in 1Password...the program does track the password change dates/times).
Second, I have an education email account that has passwords set to expire after 180 days. The only way I have to remember this is to either put this as an event in iCal or just wait until I can't login anymore and realize that's what the issue is. If I were to enter the expiration interval for this email log-in in 1Password, the program would alert me when it is time to create a new password.
Please provide feedback as I'd like to see if others could benefit from this type of feature. If enough people respond to this post, maybe the feature could become reality in a future release.