Well, you certianly don't HAVE to carb cycle, but you do have to eat over maintenance to grow. That one is a law for a natural, and it's a law you won't know you're following if you don't track your diet like your life depends on it, at least for a little while until you have a better idea of the caloric values of what you're eating.
As for when to switch programs, eventually you'll almost certainly stall with a specific program, even with the right diet. That's the time to try something else. It may be in 3 months, 3 years, or 13 years.