Cell phone batteries in today's phones can lose their capacity to hold a charge by as much as 20% after 300-400 cycles. What's a cycle you may ask? A cycle is the equivalent of using 100% of the battery. For example, let's say you wake up on a Monday and your phone is at 100% because you charged it overnight. You go through your day and you look down and you're at 40% (if this is you at noon, you're not alone either but that's a story for another day). If you charge it back up, the next time you use 40% of it's capacity you've used up 1 cycle. 60% usage on day one plus 40% usage on day two equals one cycle.
Fortunately, there is a solution. iTech has trained device technicians that can install a new battery into your old phone and give it a new life for as little as $39.99.