The largest users of power for the phone are almost always screen, followed by any number of other system or user apps.
According to a recent study and report from AVG (
Games, Music and Shopping Apps Hit Smartphones Hardest), the following are the 5 biggest offenders of overall performance for an android phone (and so will impact battery life);
- Facebook
- Spotify
- Instagram
- Path
- Amazon Android
Likewise, here's the 5 worst offenders for data consumption (which will also make them high-ranking candidates for battery consumption);
- Daily Mail Online
- Tumblr
- Facebook
- Instagram
- Spotify
So first and foremost, reduce the screen brightness, shorten the timeout for screen, limit the number of apps that can activate the Active Display through notifications, and reduce background apps such as Facebook and the like to less frequent updates, or even to no updates unless opened manually. Anything that causes the screen to turn on will impede battery life. Then anything that does background data transmission will also impede the battery life.
Next, try to use WIFI whenever and wherever possible. You may also wish to turn off other "radios" such as Bluetooth and GPS, for example, except when needed.
There are certainly lots of other ways to reduce battery consumption, not the least of which is to turn the phone's Background Data "OFF" and just leaving it open to receive phone calls and texts.
I am sure others will chime in here as well.
As far as the UDP versus the "cheaper" plans, cheaper isn't always better. It's inevitable that over time, we will consume more and more data, as we become more and more dependent on our smartphones for every facet of communication and activities in our lives. On the other hand, you only have so many minutes in a 24 hour period, and so many in a month's billing cycle to make voice phone calls in. So data consumption is potentially infinite, however phone call minutes being used in a month will always be finite.
There are 43829.1 minutes in the average month, so unless you're on the phone constantly for the entire 30 days (average), you'll never come close to using that many minutes, but even if you did, once you hit that number, your "unlimited phone minutes" becomes "limited" by the simple fact of time. On the other hand, data consumption isn't related to time, but instead to data speed and volume of data, so as video streaming, video calling, cloud backups and other data-intensive applications and functions continue to become more and more mainstream, and continue to use more and more data in every minute, it's only a matter of time before you will run out of data at the selected plan limits and will have to increase the cost to increase the GB allotment. Unless you are on WIFI most (or all) of the time, or you are simply not a heavy user of data, you will likely eventually regret losing UDP.