I dont think how long you have had them is the only factor here. Some people use their theater more than others and some people use multiple subs so you dont have to drive a single one as hard. I myself dont play things really loud and i dont watch alot of movies with LFE but when i do i like to feel it . The only sub amp i had trouble with was one that i thought was screwed but by the time i was done it was LOL. I did go through quite a few power supplies on my computers, but i think my old house had some pretty shady wiring and the power went out alot in that area. Since this new amp has 5 yr warranty that should be good for some time to come as long as your happy with how it sounds.

DOG is GOD spelled backwards.
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M80 V3 MY GLOSS Cherry