Originally Posted by
Don164 even a mundane task of watching a 5 minute video off youtube drains my battery by 3% or more.
That may seem mundane to you, but receiving and decoding a video stream uses a lot of CPU (which uses a lot of battery).
If you care for the battery properly it should last a day on the stock phone. Condition it when it's new, charge it when it's down to no lower than 40% and if you need more than that carry a spare battery. Constantly drawing the battery down to around 5%-10% (which most people do) will lower its charge capacity pretty sharply while it's still fairly young, and lead to a shot battery within about a year. (Run with Power Save on, which slows the CPU, to save even more power when you don't need blazing speed.)