I’ve noticed a much better battery life with my iPhone since getting my iPad. Seems it’s completely changed my iPhone usage patterns.
For one thing, I often reached over to the stand on which my iPhone rests for quick things like checking an incoming email. Even with my laptop right in front of me, it was just quicker to grab the phone. I’m not doing that at all anymore.
Another thing is wireless usage. When a WiFi network is available, I tend to have and be using the iPad anyway. Where WiFi networks aren’t, I usually don’t have the iPad with me and the iPhone’s 3G connectivity is the default. In response, I’ve turned off the iPhone’s WiFi radio. This did even more to improve my phone’s battery life, returning it to what I once enjoyed with my not-so-smart phones.
I’m definitely not regretting getting my iPad, that’s for sure.