We keep our heat at 67 all the time except when we have guests over. We will bump it up a few degrees for them during the day. We have a heat pump so keeping a constant temp prevents the aux heat from kicking on. I used to avoid the aux heat mostly because it stunk. I think that is probably because the water that collects but never evaporates in the air handler from Summer cooling would grow stuff. I have started cleaning out the water in the fall before we turn on the heater. Since that seems to help, I might program the thermostat to go down to 65 and then back to 67.