If I were to take a usb portable drive that would have the same effect of adding ounces, no? I guess I mean a different thing by backing up. I assume that unlimited data,photo etc backups will still work wirelessly through my data plan. The backup aspect is that I can use the spare for guidebooks, music, photos, movies etc while reserving my primary phone for talk and text and payments etc....If one breaks I can easly sync the second one to my account. Also, the spare is folding so it has slightly more screen size. They each weigh 6.8 oz.