If there's one Achilles' heel all portable devices share, it's battery life. If a gadget runs out of juice, you simply can't use it again until the battery receives a charge. Period.
So what are the best ways to conserve the battery life of your portable devices? There are some universal techniques as well as others that are specific to a particular device. Below you'll find links that cover the major platforms.
If there's a format you feel we've missed, let us know in the comments and we'll consider rectifying that.