This thread is NOT about making your battery last longer between charges. There are plenty of those out there with tips on how to extend your battery's charge. The purpose of this thread is to share with you some PROVEN tricks on how to extend the lifespan of your battery. Everyone knows that rechargeable batteries eventually lose their capacity to hold charge, and Li-Ion is no exception. However, there are things you can do to significantly slow down the aging of your battery. Again, these are proven (measurable) techniques, and they do not originate from the NiCd or NiMH days of charging. 1) Li-Ion is sensitive to hot temperatures. They can be instantaneously damaged by intense heat, and they can lose a lot of longevity though prolonged, minor heat. Unless absolutely necessary, try not to let the battery stay higher than 40 degrees Celcius for prolonged periods. The sweet spot for Li-ion temperature is between 20-35 degrees C. Don't ever leave your phone in the car on a hot day, or leave it in the sun. The high temps will damage the battery even if the phone isn't on. 2) Keeping the battery near full charge all the time strains the battery and decreases its longevity. In the case of the Evo, where battery drain is very rapid, this is pretty much a non-issue. But basically, keeping the battery near 100% all the time is no good. This is the main reason why laptop batteries die before the expected 2 years of life. Some people think this reduced life is because of the charger overcharging the battery, or that it's constantly doing short charges when the battery starts to lose a bit of charge. This is NOT the case. If your laptop is always plugged in, set your max battery charge to 50% and set it to charge when it trickles itself down to 25%. 3) It's not necessary to drain/discharge a Li-Ion before charging it. In fact, draining the battery could actually prevent your battery from ever charging again. It needs a certain amount of charge in order for it to be rechargeable. New batteries have a reserve charge that you can't tap into, so this is no longer harmful. But just know that you can charge your phone at any current charge level, and it's not harmful. There's no more "memory" issues like in the NiCd days. It's also not necessary to charge the battery all the way to 100%. The ideal charging practice is to charge briefly and frequently, and try to avoid charging to near max capacity. Might not be practical for the Evo, but certainly doable for a laptop. There are other tricks, but none make more difference in longevity than keeping the battery between 20-35 degrees Celcius as much as possible, avoiding leaving the phone somewhere where it can get really hot, and keeping your average charge around 50%. If you stick to these guidelines, you can expect way more than 2 years out of your battery. I have gotten 7 years out of my laptop Li-Ion and it's still going strong. My blackberry battery from 2007 is still in top shape.