My G3 XR-15 is still going strong after over 5 years. I'm hoping for 2-3 more. Of course, I'm not taking PAR measurements and comparing them to new. But with mostly softies, I'm much less concerned about minor degradation. Corals are growing very well, BTAs all have great bubble tips and continue to split, no change in algae which I hope means no shifting to red. No issues with power supply or control functions. I haven't changed any settings in 3 years now.