I try not to let them idle more than is nessasary. Why would you idle a truck all night, it's an utter waste of fuel, does it not have a cab heater on it?

I'll usually let the tractor run while I'm mincing about getting ready by which time it's warm enough or will be when I get to the field and put it to work.

I understand that idling cars and so I assume all automotive type vehicles, is bad because of they way they cool and they should be switched off pretty much straight away. My bike water temperature rockets as soon as it's stationary. Pretty much all cars will switch themselves off now at traffic lights.

Idling wastes fuel, causes pollution, makes noise and engines don't wear out as fast when they're switched off not being used.