Anyone have a good inexpensive lux meter ???

I have a crl grow and im wondering if a lux meter would be a good way to monitor my cfls life ???

preventive maintenance would be the easier n cheaper route.. every bulb has a life span just mark your base of the bulb and a calendar,then mark off your life span of your bulbs. when they get close to date change them out,also helps with warranty on bulbs"keeping track" of life span.. just a lot of money to waste IMO..