I think there's a bit of a quality control issue, or perhaps early batteries had problems. I have two G1s...a standard issue that arrived on release day, and a developer edition that I just got a few weeks ago. The former doesn't last a whole day of moderate usage with 3G enabled (but lasts about 1.5 days of moderate usage with 3G disabled). The latter easily lasts all day with 3G enabled. I charge every night, and I've never found it to give out by the end of day on days when I remember to charge it (and when I have forgotten to charge it, I've been pleased by how fast it'll charge up).

I have no complaints at all about battery life on the newer phone. The older one was disappointing, and I was afraid I was stuck with something that would never really be great.

Someone else suggested a "break in" period, but my older phone never got better after extensive use. The new phone was good from day one.

Depends on the usage. If you're using WiFi it won't last more than 3 hours or so (not kidding!) Playing music is also battery intensive. If you're not doing either of those, it lasts a whole day, but you'll definitely have to plug it in every night. Which I find acceptable.

I was a little concerned when I first got my G1 but after I settled down with my usage, I get about 3-4 days of usage off of a single charge.

I've installed power manager, tweaked the brightness settings, turned off wifi and GPS though.

It will last a 6-8 hours of fairly heavy surfing (no video, 1 or 2 podcasts) on the cell data network, or a full day of normal use/non-use. I usually leave wifi and GPS off, and haven't really had any problems w/battery life.

Truth to tell, those complaints are mostly valid. However, you can always bring the second (third, fourth, etc.) battery with you.

Battery life on the G1 is terrible. I have to bring my charger with me, if I plan on using it quite a bit that day. I hear that its the way the Android OS interfaces with the device thats the primary reason behind this. If they sorted out the battery life and added what was mentioned above, it would almost be the perfect first gen device.

Sucked at first, but now I got 3-4 days without charge. Just takes time to break in, I feel like.