How long does the battery life on your iPhone last?

About 16 hours

it depends on your settings
search for WiFi uses more power;
automatically checking for mail uses more power;
Bluetooth uses more power;
etc.

Here's more info:
http://www.apple.com/batteries/iphone.html
http://www.apple.com/batteries/

My battery barely gets to 70% each day if I don't sync or charge; but I still plug it in whenever possible to preserve the battery's longevity.

My battery stays charged for about 18 hours.

"mmmmmmmmmm....phone barley." - homer s.

It all depends on how much I've used wifi. I charge mine every night and if I haven't used wifi much the battery usually still has around 80% when I go to bed. I've used wifi heavily and still had about 20% left at night.

While at work, I leave my phone running constantly on wifi for JiveTalk so I can have my IM wherever I go, my e-mail and the normal phone stuff, and after 8 hours, I am still at ~40% or so.

That is an estimate as I have not found a way to check the legit percentages, just an estimation based on the battery bar.

my battery life on my phone is amazing I believe I charge when I can but no matter what I do it always has battery no matter what this phone has never let me Down on the battery life now that I think of it this phone hasent let me down on anything :)

heat is the iphones battery worst enemy. Never leave your phone inside a parked car in the sun. It will effect its longevity. Be wary at the beach or pool, or warm locker.

With VERY heavy Internet use I get about 5 to 6 hours. Everything else is better than that.

Lasts through the day with some to spare.

WIFI, some EDGE, music, phone, SMS.

BTW, EDGE uses more battery than WIFI.

wifi uses more than edge check the apple site leftspin

I respectfully ask you to decide for yourself.

From real-life test that you can read about here, which I believe better reflects "normal" usage: http://www.anandtech.com/printarticle.aspx?i=3036

"The same can't be said about Wi-Fi vs. EDGE on the iPhone where there's about a 25% increase in battery life when we ran the test over Wi-Fi instead of EDGE; the difference is identical to what we saw in the web browsing test. It appears that maintaining the Wi-Fi connection and using it to periodically check for email is significantly more power efficient than doing so over EDGE, despite the reduction in data traffic compared to our web browsing test.

It seems to be that how much data you send isn't the only limiting factor, but rather just polling for new data is much more power efficient over Wi-Fi."