In most, not all, places you don't need a license to install Data.
Cat 6 is just a fluffed up Cat 5e anyway. The difference is the noise canceling, and its certified to 250 Mhz instead of 100 Mhz. Of course this is my opinion and you should use Cat 6A*
*(Laughing too hard, must sit down!!! Cable classifications is another thread completely)
Certification for proper LAN/WAN installs allows you to charge more for a certified system by certified installers.