My thermostat's lowest temperature setting for heat is 45 degrees. (I have forced hot air with a gas furnace)
When I am home, the temperature is set between 68 - 70.
During the day when no one is home it is set at 45 degrees.

Some people have told me that this is not good practice because when the system 'wakes' it does more work and at the end of the day I do not save money on my energy bill.
These people have suggested that I leave the temperature at 60 or so when I am not at home (sleep mode)

Anyone has any advice on what the best practice is?