I keep mine inside an unheated outbuilding near the barn. It shares the building with implements, a farm purposed 4 wheeler, and extra hay that is overflow from two other hay barns. I have to use the tractor almost every day to haul shavings, hay, and manure. Most of my neighbors have tractors, and the ones that sit outside 24/7 look about 10 years older than they are, but looks usually don't effect how they run. I have seen rust buckets fire right up and work all day, but I prefer to keep mine in as new of condition as I can for a 30+ year old machine mainly because I cannot afford to replace it, and it is very valuable to me. I do keep a trickle charge on the battery, and with the glow plugs, it fires right up. I use Bio-Kleen, but mainly to prevent microbial growth, bacteria, and fungus from entering my fuel lines, and filter.