User profiles aren't restricted to what shells your users use, what groups they are members of, and what privileges they have been allocated. While these factors are important, so are when they log in, how much disk space they are using, and what they're actually doing on your systems. Periodic reviews of your users can help you get a better feel for how they use your systems and can sometimes help you to pinpoint problems.
Unix provides a lot of commands that can help pull together a quick picture of how your users are set up and when they are active.
The last command will show you recent logins for any particular user or for everyone. Depending on when the source file for this information (your wtmp file) rolls over, this might represent months of user logins.