According to a study by the Lawrence Berkeley National Lab:
nearly 90% of Americans say they’ve rarely (or never) programmed their thermostat because they’re not sure how to do it. But it’s really not that hard, and it’s definitely worth doing because it can save you up to 15% a year on energy costs.
The full article gives many tips on how to best program your thermostat to save money on your energy costs. Do you program your thermostat for when you are and are not home?