I SHOULD be able dump the paper off my desk into a box without breaking a sweat such that I need a shower. I am thus declaring 78°F to be outside the acceptable range of daytime indoor temperatures, and setting my thermostat down accordingly.
I'll note that I MUST be able to spend a day in my house primarily sitting at my desk wearing appropriate winter clothing without shivering intensely. Thus 60°F is below the lower bound of acceptable indoor daytime temperatures.
I document these for my own future reference, but also as a demonstration of what I believe is the correct process for determining home heating/cooling usage patterns. Please note the distinction between SHOULD and MUST, RFC-style. The upper bound is something I could potentially compromise on for monetary or other reasons, though I would strongly prefer not to. The lower bound is more stringent; a space this cold during the daytime isn't one I consider habitable.