When purchasing a mobile phone, most people consider the battery life to be one of the most important factors to determine, whether they make the transaction or not.
With the majority of mobile phones, you would most probably have to charge them every day. However, if you like streaming music and browsing the internet during the day, not to mention watching videos on the commute home from work, then it’s difficult to charge your phone. if you're regularly having to carry a battery pack just to make your phone battery last through the afternoon, then your phone quickly begins to lose its so-called 'smartness' and becomes just another chore to add to your to-do-list.
A good indication of how much power you're likely to get out of your phone's battery is to look at its overall capacity, which is rated in mAh. The higher the mAh rating, the bigger the battery, therefore mobile phones with bigger mAh capacities should, in most cases, last longer. However, you also need to take into account the other factors such as screen brightness and resolution as they also play a big part in how quickly the battery is drained.