I bought my 400w hps 27 years ago so I got my moneys worth. I am thinking about other lights but remember what the guy who sold me the 400w said when I bought it. "For one person, a 400w is good will produce enough. Whereas if I had a chick I would need a 600w alone a 400w will keep me in weed. A 600w puts out a lot of heat! And the old 400w flowers 8-9 plants well. I am open to new ideas but am planning on buying another mechanical ballast, 400w light. Hope it lasts 27 years. Thank you... The Poet... .