Note that the lifetime of a bulb is quadratic, if not exponential, with its wattage. The 100W bulb always lit in the living room will last 6 months but a 30W w

Note that the lifetime of a bulb is quadratic, if not exponential, with its wattage. The 100W bulb always lit in the living room will last 6 months but a 30W will do a decade.