Key Management Server for Vista : check in frequency

Hello.

I just setup KMS on a Windows 2003 Server. I deployed 26 machines, KMS

activates clients and everything is fine, except for the fact that my

machine and my co-worker's machine checks in with KMS 2 to 3 times per

day. The kiosk machines only checked in once so far. I was under the

impression that KMS clients only checked in every 7 days, so why is my

machine requesting activation from KMS every day?

My workstation is activated and is working fine, but I'm wondering if

this is a problem or not.

Thanks,

Adam