Over the past couple of days, I’ve been testing and comparing the battery life of the iPhone with my previous phones. My Sony Ericsson t68i lasted a long time when I first got it, easily allowing me to go a week before having the recharge it. The Blackberry drained more quickly, forcing me to recharge every three days. Of course, the battery in the Blackberry was older, so a newer one might allow for longer talk and standby times.
Of course, with the iPhone, I’m doing much more than making calls. I’m browsing the Internet, listening to music, and taking notes. In almost two days, my iPhone indicates the battery is down to a quarter tank. The Usage tab of Settings says I’ve used the iPhone for 7 Hours. Standby indicates 1 Day, 21 Hours. Considering all that it’s doing, I say not bad. Still, I’m going to have to remember to take the charger with me on all multi-day trips.
What are other people’s experience with battery life on their iPhones?
tow.com 
After my second full charge I used it for a bit over 10 hours with standby at 1 Day, 12 Hours before no juice. And this is mostly surfing on the web, checking email, using it as MP3 player during my daily commutes, putzing around with Youtube. It seems to last me just barely 2 days. Basically it’s going to have to be charged every night just to be on the safe side.
It’s like an iPod battery if you keep the cell radio off (airplane mode). After a few hours of use a few days in a row, it’s dropped to ~90%.