You don't have to take the test again. I believe you only have to take the test if your license expires at the end of the ten years AND you wait more than two years before renewing it again.
I did get my novice license (or whatever the lowest license is called) but never got an old borrowed radio to actually transmit. Then life kind of got in the way.
I keep meaning to get back into it, the sstv and various data networks are really cool. I really dig the analog tech.