I will say, the controller has lost my programming a few times when I've gone to make adjustments and had to start over which is very annoying. But ideally you won't have to change it ever. I've had to change mine when I decided to start keeping higher light corals and needed to slowly ramp up to accommodate, and again when I added the third fixture.You won’t regret getting these lights. I have used them for over a year with out any problems. Some people complain about the controller. I think it’s because most people are familiar with a touch screen.However once you set the lights up. You will probably not mess with the lights much. At least that has been my experience.