For peace of mind a baby Listening Monitor, particularly those models with sound lights will allow you to see and hear your babies sounds.
Once your baby makes a transition from cot to bed a bed-guard will help stop baby from rolling onto the floor. A folding bed-guard is useful for travel and for keeping at grandparents or child minders for nap time.
Do not place a chair underneath a window, even if it is closed. Use a window lock to safely lock open a window for airing the room, to prevent it from opening further.