Android: For those who root their phones, custom recoveries are a godsend. Few are as useful or as popular as the Team Win Recovery Project (or TWRP), and now you can download a TWRP installer straight from the Play Store.
Custom recoveries allow you to back up your phone, install custom ROMs and do other maintenance tasks on your system. The built-in recovery only lets you scroll through tedious menus with your power and volume buttons, but TWRP and other recoveries like it enable the touch screen and make it much easier to do system-level tasks.
The new official TWRP app lets you keep TWRP updated, which is normally a tedious process of downloading the new version from the developer's site and flashing it each time one comes out. While there are third-party recovery updaters, it's nice to finally have one from the same people.