This is a question that we hear often at DrStonerBikes, and can be answered a a couple of different ways. Are you wanting to know how far you can go on a single charge, or the life expectancy of a battery?
There are a number of variables n answering this question in terms of how far can one go on a single charge. Batteries vary in size and Ah; the weight of the rider, the number of hills you will tackle, how much throttle or pedal assist you use will all impact the distance you can achieve on a single charge.
The size of tires will make a difference in the distance you get on a single charge too. Fat tires have more surface resistance, whereas narrow tires glide easier.
Battery life? A lot of that depends on you and the batter care you give your battery. How you store and charge our battery will make a difference too. On average, you should get about 1500 cycles from a battery, or for the average rider that is about 6 or 7 years of riding.