at room temperature

I guess it might depend a bit on local climate, as well. You can get away with stuff in Lancashire in November which you can't in New Orleans in July. (And, of course, vice versa.)

FWIW I gave up on butter for spreading -- I use one of those nasty fake butter things made from petrochemicals and herring. But I still keep butter around for sauces, pastry, and, when no-one's watching, frying.

Peter