A few days ago we added some enhancements to the user permissions in the Admin --> Users areas:

Now, when you open an existing user for editing or add a new user to your account, you'll see three different types of users, and some permission/role enhancements.
There are Admin users:

Standard Users:

Standard users can't access admin features, and you can define which areas/modules they can't access. By default standard users have access to every non-admin feature and screen, but you can set restrictions which remove these areas for them. Check a box here to restrict access to that area/module.
And Vendor Users:

Vendor users are intended to give your contractors, repair & maintenance staff, and vendors access to your SimpleRent work orders.