Battery life has been my most significant complaint about the G1. So I decided to find every instance where power was being used unnecessarily and eliminate the waste. Following these steps significantly extended the life of my battery. And I've continued to use the features that make the G1 worth owning. Of course a lot of these options apply to other devices as well. Some are specific to the G1.
Recalibrate the battery
I thought this problem was resolved years ago. I was wrong. Batteries still develop memories. And if you haven't run your battery all the way down a few times, you're not getting everything you can out of it. The process, according to T-Mo tech support, is: use the phone until it dies. Charge it up until the indicator light has been green for at least two hours. Repeat. I did that, then repeated the entire process again. Four complete drains, and my G1 battery's lifespan is at least 50% longer than it was before. At least. Of course I've changed some of my habits as well.
Power Manager
This is probably my favorite app in the Android Market. It allows you to set up profiles and automatically select them based on user-defined triggers. For instance, turn off GPS when battery power falls below 30%, or turn up the screen brightness when the phone is plugged in. You can even look at stats to see where you waste the most energy.
Personally, I wouldn't recommend doing any of these things. Leave the monitor off. Set up the most efficient profile you can live with, and then manually turn services, like GPS, on for the few minutes you need them. Power Manager provides a simple interface for toggling lots of processes, so go ahead and put in on your home screen.
Inside the app, you'll see a knob for switching between 2G and 3G. If you have Wi-Fi in your home, switch to 2G. That's two taps to get 3G before fetching data while away from home. The saved power is worth it. You're not worried about excessive finger exercise, are you? Turn off the monitor, unless you want to change profiles automatically.
Now hit the menu key and create a new profile. Enter the name and description and hit O.K. You will see a list of categorized controls.
Trigger
This is just for those who want automatic profile switching. I think it's best to always preserve energy, so I won't be covering the option. Running the monitor in the background takes juice.
Sound & Display
Ringer mode: personal preference
Brightness: can only be dropped to 30/255 in this app. I'm not sure why, but we'll fix that later. Leave this option unchecked.
Screen timeout: go for the 15 seconds. Increase it only if it becomes a hassle.
Wireless controls
Wi-Fi: personal preference
Bluetooth: personal preference
Location
Use wireless networks: Disable
GPS: Disable
Data Synchronization
Auto-sync: Disable, unless you *really* have a reason.
Now hit your back button. The profile has been changed. Toggling the options on the Power Manager home screen will not update your profile. So go ahead and switch things on as you need them, but remember to turn them off when you're done. If there comes a time when you can't remember what all you've changed and you want to get back to being efficient, just tap your profile name and you'll be running lean and mean once again.
As I said, Power Manager has a minimum screen brightness setting of 30/255. You set the profile not to mess with your screen brightness, right? Go ahead and drop it to 0. (Settings -> Sound & display -> Brightness)
One other thing that Power Manager neglects is Wi-Fi notification. (Settings -> Wireless Controls -> Wi-Fi settings) Un-check Network notification. While you're in here, let's make sure you don't get stuck with a surprise bill after your next vacation. Back key, Mobile networks, un-check Data roaming. (Settings -> Wireless Controls -> Mobile networks)
If you follow all of the steps above, you will see a significant difference in your battery life. If you are more disciplined than myself regarding Wi-Fi and Bluetooth, you just might forget about your phone's battery issues all together. Conservation has worked very well for me, and I still use the G1 for everything I want to. I'm just more conscious of what I'm asking from it.