I am programming in assembly and my CodeWarrior 30-day evaluation period is about to expire. My understanding is that I can continue to use CodeWarrior after the 30 period and don't need to do anything, even though the pop-up screen says I can use CodeWarrior until the current license expires.
Usually after the evaluation period expires it is automatically switched to free Special Edition (if such version exists) so you don't have to register it.