Optimize iPhone autonomy and ergonomy
I own an iPhone 3G since one month and I found some weaknesses, including it’s autonomy and ergonomy, and I want to share with you some tricks to optimize the autonomy and it’s usage.
Autonomy
From start, autonomy was at least deceptive, while I used it only to hear music, few web surfing and few phone calls. But even with a lightweight usage the battery autonomy was under 2 days 
With few tricks you may change your battery life
- Deactivate Wifi when you didn’t use it, it draw battery faster than anything else
- Deactivate 3G when you didn’t use it
- Deactivate automatic mail scanning, do it manually, temporarily reactivating Wifi or 3G
- Dim the screen as much as possible
- Use the iPod function with the included earphone (that have a button), a phone-headphone (with button and micrphone integrated) or Belkin adapter for you hifi headphone, it will improve the useability and the autonomy at once!
With these little tricks, you could come from 1 day and half to 3 or 4 days of autonomy on your iPhone.
Ergonomy
Not a good iPhone or MP3 Player when used with a good hifi headphone, the worse I know. I began to use it with my Sennheiser PX-100 hifi-headphone and was tired to do 4 actions just to go to next tune: tap on menu button, slide from left to right, tap on next tune (on screen) then re-lock the iPhone (upper button)…
For the audiophiles, there’s an accessory that change the life: Belkin headphone adapter for iPhone. It features a microphone (for phone call), a button, and an headphone ouput, to connect your audiophile headphone (Sennheiser PX-100, Koss Porta-Pro or Grado SR60/80 for example).
With it’s button you will be able to go to next or previous tune, pause/play the music, tak a call, hang-up, and stay with your good hifi headphone : the best of the worlds 
This is a must buy for those of us that have one good hi-quality headphone and wont cope with Apple’s one.