It matters on how your house look like - some people let degus run in the bathroom, some in the hall, some in living room. It should be somewhere where degus don't have access to receptacles and cables, because they would chew them and could get electric shock. You should let them run at least once a week, the more often you can, the better. Bring them to this place with their cage too, it's better just open the cage so that degus can go out and return back as they want. And keep an eye on them, at least when they are out for the first time and you don't know what could be dangerous for them. Some of known dangerous things are: open window (close it also when you think that degus can't reach it), open toilet, electric cables, toxic plants.