Will the teenagers actually use it?

That is the honest question behind a lot of these enquiries, and it comes down to whether the room is comfortable. A cold building at the bottom of the garden gets used twice. A cosy one with proper heating, good wifi, decent seating and somewhere to put a drink becomes where everyone ends up. Designed for year-round use, it turns into the place your family and friends gravitate towards rather than a shed with a dartboard in it.