Yesterday I made my Samsung Galaxy Ace much faster and improved the battery life by 50%: I uninstalled all apps I do not use several times per day and Facebook. I now have much more free memory, the phone feels much faster, the battery lasts longer and it does not run as warm as it did.
I really have to unlearn the habit I got with iPhone: I used to install apps that seemed interesting and then I might try them out later. I also had apps I had only used two or three times but thought they might be sometimes useful. That's not something you can do with an Android phone. It teaches you to live lean.
Today I learned it is a bad idea to take a call while listening to a podcast. When I had an iPhone and was listening to a podcast or music, a phone call would interrupt listening but it would automatically resume when the call ended. Not so with Android. The podcast app froze when the call ended. Android did eventually pop up a dialog telling me the app had become unresponsive and offered to force quit it. I did. But the phone was unusable after that. I tried to make a call but the screen went blank and I got a dialog telling me com.android.dialer was not responding. I tried to restart the phone. It would not turn off.
I have also learned listening to music takes around 50% of cpu. If I press the Home button to exit the music app and try to do something else, the music playback starts breaking up. It's like I was back in mid-1990s when my poor old 486 PC could barely play mp3 files, but only if I didn't do anything else at the same time.
I can only think the Android phones decode music using the main cpu. My old iPhone 3GS never missed a beat even when I did something else while listening to music. Maybe iPhones have dedicated hardware for mp3/aac decoding?