All the time even when I'm going on really short journeys.
The seatbelt is there to protect the driver and the passengers.
Also this may sound like a bit of a rant but I hate when people get into cars, to go to a shop about 5 minutes away and they refuse to put their seatbelts on, because apparently car accidents don't happen in five minutes. No, I strongly believe that the road is a very unpredictable place, were anything can happen, anything.