I usually idle just long enough to check my mirrors, check my fuel level, snap my seatbelt closed and pull down the parking brake.

Learned not to idle too long when I drove a car before without a thermostat. If I idled it, it would take forever to warm up. And it's bad to run a car "cold" for that long. If I drove it after just half a minute's idle, within a kilometer or so, it'd be warmed up.