We're looking to convert our triplex to a duplex so we have more room for our family of four (4 and 7 year olds). I am worried though that after we do the reno, we'll just have the same problems, with a bunch of unused rooms. (One caveat is that we're trying to limit screen time with our kids, so we can't just put a TV in one of the rooms and let them do their own thing.) Where do your kids play?
Out house has 3 x bedrooms (one used for working from home), a bathroom, and ... the other room. That's where playing happens. The room is a combined lounge / dining / kitchen, and most playing happens on the floor or the dining table. Drawing, Lego, reading, homework, light-saber fights, model rocket assembly, knitting, other craft stuff, ...<p>Soccer, handball, running around with the dog, etc, happen in the back yard (a 5x10m or approx 15x30ft area, with some decking, some grass, and some concrete).<p>Bike riding, kite flying, etc, happen at a park.
When I had young children the answer was: wherever they want (with some obvious limits, of course), and outside as much as possible. Limiting screen time has all kinds of solutions.
Mostly in their rooms.. crafts happen in the kitchen/dining area.<p>Lego stay in the bedrooms.<p>No TV's save the main one in the living room.