Would a vacancy sensor switch be good in my bedrooms and my kid room?
No one ever wants to shut the lights off! If not, what type of switch would be good?

I just installed a Leviton "occupancy" motion detector switch unit in a closet. Turns on by itself and off after 3 minutes of inactivity. A "Vacancy" switch must be turned on manually but turns off with inactivity.

Probably no worth the cost. Probably take you several years to recoup the cost. Easiest thing to do would be to install LED bulbs. Cost of burning LED bulb is minuscule.

hk...
if we assume 1kW = $0.12 and the LED is 13 watts, then...
One month (always on) = $1.20
One year (always on) = $13.65

I agree, buy LED lamps and withhold their allowance until they turn them off!