Your smartphone is a minor miracle, a pocket-sized computer that can fulfill almost every whim. But none of its superpowers matter a bit if it runs out of battery life. The first rule for extending your battery life is not using up all your battery life playing Candy Crush and walking around with Wi-Fi and GPS enabled when you're not using either and really, really need your phone to last that extra hour. But aside from that, there are some basic rules for care and charging, and they're the simplest baseline for a healthy battery.
Top it off
Battery memory is a real thing, but it applies to nickel-based batteries; your trusty sidekick (literal Sidekick or otherwise) doubtlessly has a lithium-ion battery, and it needs to be treated a little differently. Specifically, it should be topped off whenever you get the chance.
Keep it cool
It's easy to worry about bad charging habits thanks to the training we've had from old rechargeable batteries, but lithium-ion batteries have a worse enemy than sub-optimal charging: Heat. Your smartphone's battery will degrade much, much faster when it's hot, regardless of whether it's being used or just sitting around doing nothing. At an average temperature of 32 degrees fahrenheit, a lithium-ion battery will lose six percent of its maximum capacity per year. At 77 degrees, that number jumps to 20 percent, and at 104 degrees it's a whopping 35.
Sure, it's not exactly practical (or sane) to keep your phone in the fridge, but it's worth going out of your way to prevent long stays in hot cars and the like.
Avoid wireless charging as much as possible
Wireless charging can be incredibly convenient if your phone can do it, but it's not without its disadvantages. The inductive, wireless chargers out there today can generate a fair bit of waste heat.
And while wasted energy is just a bummer in general, that heat will also toast your battery in the process. That's no no. It's a little less convenient, but standard plug-in charging is going to keep your battery in better shape, especially if you're some place warm to begin with.