Depends if Leno wants to semi-retire and take a bit more time off or not but he's a famed workaholic.
Even then, they could give him a lighter schedule at NBC and he'd spend the rest of that time touring, doing stand-up. It probably has more to do with how much time NBC is willing to pay Leno for.
Mostly, I don't care. The only shows I watch on NBC anymore are Law & Order and SNL. (And I'm looking forward to The Tonight Show with Conan O'Brien.)