Time Machine Only Does Full Backups

Hi Group!

Can someone tell me please why Time Machine always does a full back up of my machine? I thought when i initially set up Time Machine for the first time, it does one FULL backup, and then incrementals after that.

AM I WRONG?

I can't get TM to do the incrementals. It always wants to do a full backups! I have a 1 TB drive in my computer and a 1 TB drive as my TM drive. And data combined on my computers HD is around 650 GB.

Please advise.