I don't really pay attention to what the temperature is, but if my hands feel really cold I wear gloves particularly at night during the winter. Usually I will just wear fingerless ones so I can still type or do housework easily in them.
I used to hate gloves because they make it hard to use your fingers, but after a bout of chill blains a few years ago, I'd now rather have warm hands and less dexterity than frozen hands. If it is not too cold, then I wear a pair of fingerless gloves, which I love.
I will if it gets close to zero, usually not before. It also depends on what I'm doing outside. More often than not, I am only outside for a few minutes, and thus I don't bother, but if I am going outside for an extended period, then yes, I will.
I wear gloves when it is very cold or I feel cold as I mostly walk to destinations and gloves make a difference, I think they look smart as well. Fingerless gloves are handy for some events as are gardening gloves too.