Active Directory Best Practices and Questions

unknown

Just wondering the best way to use AD for authenticating users. I have both the built in AD and a Radius working on a test SSID and wondered which was favored.

Also how often does this authenticate? Is it only at first connection? When people leave or are fired is there a way to remove user without having to constantly making people re-authenticate?

Just looking at a better way to authenticate our inside network and any tips or info would be great! Thanks!!