This is going to sound weird, but it's been bugging me for a couple days now. There's always the time travel paradox problem where you'll destroy all of existence if you touch your past or future self. But don't they say that every molecule the human body is switched out every seven years or so. So your seven years in the past self has no physical relation to your now self, just some shared memories. There really shouldn't be any problem with a person sharing the same space as a future self, because they aren't really the same people. So what's the big deal? Bring on the time travel.