I generally err on the side of refrigeration. I don’t (ever) refrigerate “liquor” (plain distilled spirits), nor very sweet, especially higher ABV, liqueurs (I don’t know if it’s the sugar or the alcohol, or the combination of the two that “preserves” their flavor, but they they don’t seem to change much at room temperature even over long periods of time.) I rarely have “cream liqueurs” in the house, but unless they’re going to be finished in a couple of days (like at holiday time), they go into the fridge even before opening. i’ve had Bailey’s “go off” eventually even when kept in the fridge (“off” as in “pours out in chunks like spoiled milk”, not “minor changes in flavor” ), and I imagine that would happen all the sooner at room temperaure. (I think even the label advises refrigeration.)
If I expect to have keep them for a while (more than a few days), even higher ABV fortified wines but “pre-oxidized” wines like sherry go into the fridge (and come out long enough before serving to warm up), and fino definitely goes straight into the fridge. Other fortified wines are a greyer area. I do refrigerate Vermouth (which I mostly use for cooking anyway), but I’m quicker to refrigerate those with less than 16% ABV and that are dry/dryer. Except for some very sweet but high-acid dessert wines (like German Auslesen or sweeter) which I might leave out during the Winter for as long as a couple of days, table wines go straight into the fridge. I find that some very heavily-extracted but young wines (usually but not necessarily reds) can hold up for a day or two at room temperature, but in terms of any improvement of their flavor, my own experience is that that’s more an issue of oxygenation than “temperature”, and once they are oxygenated (usually by decanting, but maybe just by the air that enters the bottle as the wine is poured out) storage at room temperature doesn’t do them any favors… And I notice a decline in “ordinary” table wines very quickly if they’re left at room temperature, though for whatever the reasons, whites are generally more quickly affected than reds. Even in the fridge I find them overly oxidized after even a few days unless they’re vacuum sealed, and if they were open and at room temperature for several hours before sealing and refrigerating them, even a good vacuum extends their life by only so long.