MONTHS OF DAILY USE of my Nokia Lumia 800 have resulted in 16 hours between recharging the phone, thanks largely to a combination of the pre-installed Battery Saver, the clever functioning of several paid apps and controlled usage of email.
I toggle the Battery Saver "on" during most of the day because I want to prevent the phone from making 3G or wifi data connections automatically. Since I've four email services on my Nokia Lumia, they reduce the phone's battery capacity by at least one hour every work day, in my experience.
I don't run ad-supported apps during my work day because they poll a lot of data traffic and run those advertisements inside the apps. Instead, I've bought nearly every app on the Lumia, reducing battery drain due to advertising traffic.
I also have configured as many screens as possible to black backgrounds, another technique that reduces the power required to display the main screen.
With these considerations on board, I can better extend the daily life of my phone and handle voice calls, video recording and YouTube playbacks. The only way I've minimised the power requirement for those three tasks is to remain stationary in a strong area of reception.