As everyone has said, you don't.
You should consider whether passwords (single-factor authentication) are adequate for your needs. Even if all your users abive by password guidelines, there are other risks such as shoulder-surfers and key-loggers. A much better solution is two-factor authentication. There are various dongles that you can buy, or there's the free and open Google authenticator that can be installed on any smartphone. The user can have a fairly simple and easy to remember password and never needs to change it, because there is also a six-digit number that changes every thirty seconds, without which their password is useless.
Should perhaps add, a shoulder-surfer doesn't even have to be in the building. In my student days, somebody bought a telescope in, and showed everybody what could be seen through the windows of a tower-block hotel the better part of a kilometer away. Nobody bothered drawing the curtains on the 14th floor! Today, they probably would in a hotel by night, but in an office by day?