I did mine by the book, it started the first time, never got a code, and I gained some lost power that I never knew about. I didn't think the job was as bad as people say, but it's great to have a helper to two, especially to hold the cams.
I had a 1381 code two weeks before the scheduled timing belt change, it "fixed" itself overnight, so I drove it until the change. I think some cars can get away without loosening the cam gears, while others can't. I did it the safe way, plus with the prior code I think I would've had timing problems if I didn't.