I usually recommend that the change in temperature does not exceed (3) degrees up or down.
Any amount over that will require more energy to heat the space.
For more information:
Read "How much energy is saved by turning down a thermostat even by 1 degree? Is there a statistic available?" a Q&A answered by Michael Holcomb.
Also, read "Does a programmable thermostat really save 20% on my utility bills?" a Q&A answered by Steve Saunders.