For a long time people thought it was best to let their battery wind down as close to zero as possible before charging it back up. This is mainly because it was believed that a battery ‘remembers’ where it started getting charged from and takes that as its new zero per cent.
However, it’s now generally accepted that you should try and keep your phone regularly topped up throughout the day, keeping it between 50 and 80 per cent as much as possible. Around once a month you should drain it right down to calibrate the battery, but in general you want to keep it as far away from the red line as possible.
Regular mini charges will not only keep it from using up the limited supply of charge cycles, but it will also prevent it from getting too hot when charging from 0 to 100. Heat also spoils battery life, so avoid that at all costs. Also, it means you’re unlikely to run out of juice for when you really need it!