Last year I replaced my 8D AGM house batteries after having installed them in 2007. They were the West Marine AGMs made by DEKA- amazing run! So , hadn't thought about my start battery until last weekend when the motor wouldn't start- sure enough, turned battery switch to "ALL" and away we go. Tested my 10 year old West Marine AGM A824M and it was finally dead. Again made by DEKA. my point is - it is certainly worth spending the extra to buy quality - who would have thought you could get 10 years out of batteries in a BOAT!