If you want to ensure passwords adhere to a minimum length on a Cisco router, there is a simple command you can use to enable this feature: security passwords min-length <#>
To configure it, simply enter global configuration mode and type the following:
R1(config)#security passwords min-length ? <0-16> Minimum length of all user/enable passwords R1(config)#security passwords min-length 10
Here's how the command works when you try to configure a password that is too short:
R1(config)#enable password cisco123 % Password too short - must be at least 10 characters. Password configuration failed
R1(config)#enable password cisco12345
Obviously if you have the ability to configure local passwords on a router, you would most likely have the ability to remove this command. However, I would imagine it could serve as a simple reminder if anyone tries to change the password and forgets to use a longer one.