1. Before answering we must first note that the bulb, its burnout, and its replacement are all factors of psycho-socio-technical system, which must first be understood as a whole. Sure, we could easily replace the bulb, with, say, one guy, but then we’d be reinforcing your neglect of the system and your dependence on easy fixes.
2. Two! One to spin the room and one to hold the bulb still.