The Packing app allows forgetful travelers to create and edit unlimited customizable packing lists and check off items during packing. As you create each list, discover new ideas from sample lists. The app also allows you to create a pre-departure to-do list. The latest version features the ability to filter lists by bag, person or both, as well as separate checked and unchecked bags. The app is available on iPhone and iPad for 99 cents -- less than the price of a forgotten toothbrush.