Posted By IndyGEO on 02 Feb 2011 03:38 PM
It only comes on if you need it...
"If" aux only comes on when you need it, then it's fine to leave it enabled. Unfortunately some thermostats call for aux when it isn't needed due to it's logic (or lack thereof), and/or due to the setup options selected.
Also, user input (programed or manual) may also be responsible for unnecessary aux engagement.
I agree as well to re-enable aux if the house is unattended.