Well my wife and I got the inspire on launch day. Since then we haven't been able to get more than a work day out of them. The phones go on the charger at night around 10pm, and then come off the charger around 5am. Even with little use I'm getting 15% battery warnings by 6 that evening. I guess this isn't typical so what's the fix for poor battery life?
let us know what is using up power: settings--about--battery--battery use
-Keep brightness low, it's a big ol' screen and takes a lot of power to keep it lit bright (on about 1/6 brightness on mine, it uses 51%)
-Keep syncing and push notifications to a minimum. Only the necessary ones should have that (I for example don't have any syncs or pushes that automate themselves)
-use WiFi if possible. Searching for phone signals takes a lot of juice as well
-try to start better charging habits (charge in the red, turn it off if you can while charging, etc)
It's a small battery, so it takes some adjusting your settings and baby sitting it to make it last. Look into more chargers, portable USB chargers for on the go, DO NOT buy extended batteries- they are almost all fake or lieing about the Miliamps.
Also, some debate about rooting increasing battery life, mostly cause those ROM's are designed to be more efficient and you can remove bloatware that may open up and work in the background...I'm looking at you AT&T Navigator