They say a person's average attention span nowadays is just 8 seconds. And when it comes to gadgets, apparently T-Mobile thinks it's 3 smartphones a year. The new JUMP On Demand plan being offered by the un-carrier allows users to trade-in their devices up to 3x a year, and without even paying a monthly fee. Sounds too good to be true right? Apparently, their flamboyant CEO John Legere doesn't think so and will even convince you, with NSFW language to boot, that it is true indeed.