I don’t exactly understand this

I have a habit of going to work and forgetting to change the thermostat.  It isn’t too bad when my husband leaves after me, but usually I am the last one to head out.  I am supposed to be turning the air conditioning to a higher temperature, so we aren’t cooling the home when no one is there.  In the winter, the thermostat is to be set really low, so the heating isn’t being wasted. I know it should be a simple concept, but I just don’t remember.  My mom and dad always had a programmable thermostat. From as far back as I can remember, dad had the thermostat programmed to change temperature from right after they leave until right before someone got home.  It was automatic to have the house cooler when you got home in the winter, or warmer in the summer, because of the programmable thermostat. The house my husband and I just bought, does not have a programmable thermostat.  Normally, I would just go out and buy a new thermostat and my dad would probably even install it for me. My husband works at a home improvement store. You would think that he would think to buy a programmable thermostat while he is working.  Why is it not okay for me to reset the thermostat, but it is okay for him to forget to buy a new thermostat. I don’t understand the logic there. Maybe I should just stop in there while he is working and buy the thermostat that I want. If he sees me buy it, then he can’t yell at me anymore and he’ll understand that it is partly his fault.

HVAC maintenance