I've got one of the truly ancient thermostats that has a little capsule of mercury in it. You can't even buy them any more. What I usually do is to go through a cycle of turning it down a degree, letting the temperature settle, and then deciding if I'm still comfortable. If I am I repeat the process, turning it down a degree at a time until I feel chilly. Then I turn it back up a degree or two. The idea is to maintain the lowest temperature (and therefore the lowest bill) that doesn't involve endlessly feeling cold. At the moment I think it's set to 63-64. Sometimes in the evening we turn it up a notch or two.
My house is an old one that doesn't have central heating in all the rooms. My study doesn't have a radiator in it and if I leave it closed up (which I usually do to stop the cat getting in there) it often drops to the low 50s and sometimes lower still if we have a sustained cold snap. I keep an electric radiator in there on a timer to try and stop it dropping below the high 50s. It's hard to do much work when the temperature in there is 48 and the radiator is working overtime trying to get the heat back up. Part of the problem is the exposed concrete blocks - as soon as I can get the blocks smoothed off and insulation panels put in that will make a huge difference - when it's really cold in there my thermal camera shows the face of the concrete blocks at about 45 degrees and the inner face of the panels I have got in place so far at more like 56. Once I get drywall over the top of the insulation panels it should get better still.
Trying to balance maintaining comfort without being financially drained is tricky in the winter. A couple I know hated their house because they wanted more space. So when they found a house that was cheap because it had sat empty for three years they bought it. They love having the space but don't like their projected heating bills - they are expecting to pay something like $5000/year to heat the place. It's a magnificent house but that bill to heat it is ugly.
