Floor - to glue or not to glue

Floor frame built, ready to lay down the plywood. Is it better to glue and screw or just screw it down - same goes for the walls attaching to the floor frame. I'm assuming the floor/walls would be the first thing that would rot and it would be a lot easier to take up and replace if it were just screwed down...but then again, if properly sealed, it probably wouldn't rot for many many years; I'm thinking spar urethane and then prime-n-paint. I'm sure it's a matter of personal preference, but would just like to know what the masses have to say about it?