I’ve had these for 2 months so can’t speak to longevity. I will say I used them in a corner with several indoor plants that just weren’t getting enough light. The difference in my plants is OBVIOUS. I have read a lot about grow lights and how specific they need to be, how bright, what light frequencies, etc. All i know is these were really easy to install; the clips work great on the shelf and stay put. The time is incredibly simple— I don’t even think i needed directions to figure it out. These stay on the 12hr timer. EVERY PLANT (5 peperomia varieties, a string of hearts, coleus propagations— which all rooted and sprouted new leaves— and a thanksgiving cactus) under these lights has exploded with growth. After considering grow lights for so long, and thinking they may not make a difference unless they were really expensive, I’m kinda mad I didn’t get these earlier. My plants have all perked up and are showing new growth where they had previously been stunted. The price is reasonable, and while i can’t speak to the specs or the science, im very comfortable recommending based on the growth and vitality i’ve witnessed in my own plants.