It almost seems silly to have keys for the tractor with the exception of keeping children from starting the tractor. Since they are all keyed alike, and when the ignition gets older, you can practically start the tractor with a screw driver. All of the military vehicles that I drove for years had had a simple turn to start switch like a tractor. To the left for the glow plugs, and to the right to start. They then had a retractable cable that was attached to the vehicle that you would lock through the steering wheel with a padlock. As far as I can tell, they have been using this system since about World War 2, and if you lose a key, you cut the padlock. The only reason I say this, is because they are all keyed alike, and that makes it tricky if you are taking the key out for security purposes so it is not stolen. I do however agree with having it locked all of the time, if there is any chance that a kid could climb on the tractor when you are not around. I have seen a few tractors over the years started by kids, and driven around a field. My friends sister actually drove one through the side of a barn when we were kids, and she got very lucky. Anyways, sorry to go off topic, but I would make sure that you have several spare keys, because depending on the ignition, sometimes, the keys have a tendency to fall out when you hit a large enough bump. Take care, and enjoy that new tractor!