JTB FlexReport will help you to see the license usage over the time and help to justify new purchases. This will help you to decide when and how many licenses you will need to purchase next time. Instead of guessing and purchasing more licenses than you really need you can save your money using JTB FlexReport.
If you have cascading licenses or multiple versions of the same application, you can combine the various separate reports to get a total usage. This way it can help you to comply with that your company are not using more licenses than allowed as can be the case if you for example have AutoCAD 2008, AutoCAD 2007, etc on subscription from Autodesk.
You find JTB FlexReport here.