I remember when I was on Snow Leopard my battery usually 'behaved' logically - I had 5-6 hours of proper battery life and my Macbook Pro (2.26GHz) was a late 2009 model. As soon as I upgraded to Lion, my battery only held about 2 hours plus charge. It shows 6-7 hours and then quickly drops down to 2 plus hours. It was as though Apple was encouraging users to change their batteries with the Lion OSX upgrade. Now with M.Lion releasing soon, I don't know what we should expect. Hopefully Apple has fixed this problem. P.S : I did get my battery checked at Apple Store and I was told that my battery was healthy and I should be able to retain 6-7 hours of charge. But, the battery; of course fails to last that long. I was told to replace my battery which I felt was foolish to do as : 1) It's expensive 2) It's still healthy according to Apple Employers at least !