I don't particularly agree with him, either.<p>If you're doing sensible things, like turning off push e-mail when you're in the office, not keeping 3G on when you're in patchy coverage, etc. it should last you the day. I live in London, where there's 3G signal _everywhere_, which helps a bit.<p>We really need a developer to step up and design an iPhone app that would let you save and easily switch "states" that could flip all of the various power-management affecting settings at once. (3G, push, GPS, WiFi, etc.) Someone who does this could easily sell it to virtually every iPhone owner.