In our first complete day of testing iPhone after a complete charge, we ran the battery down to 10% with just shy of nine hours of usage. (iPhone tracks "usage", which is all the time it spends not in standby since its last complete charge.) A majority of that time was spent using Internet via WiFi, with some EDGE, occasional photo taking, and about an hour and a half of phone calls.

Apple claims up to 6 hours of Internet use, or up to 8 hours of talk time. We didn't measure closely, but our first day appears to bear out these claims. It will take a few weeks of use to get a sense of how long the battery lasts with typical a day to day usage, but we guess that we'll be charging it every two or three days as we drop to less frequent use.

(We also learned that iPhone warns you when just 15% charge is remaining, and again at 10%.)

iPhone's battery is not removable. Apple offers an iPhone battery replacement service for about $85. (Apple also will rent you an iPhone for $29 for use during service.) Disassembling iPhone is not for the faint of heart; when the time comes to replace our battery, we'll have Apple do it. Apple says the battery should be good for 300 to 400 complete charge/discharge cycles. If iPhone lasts two to three days between charges, the battery's life expectancy at two to four years. (Actual results will depend heavily on usage patterns.)