To be sure your lights aren't working against you, The Department of Energy recommends cleaning them every six months to two years and throwing out bulbs when they start to turn yellow and dim.

A rebate program for energy efficient light bulbs has been so successful that Austin Utilities will discontinue it. The $2-per-bulb rebate will end March 31 because of high market penetration ...

To be sure your lights aren't working against you, The Department of Energy recommends cleaning them every six months to two years and throwing out bulbs when they start to turn yellow and dim.