If you use your tractor close to daily then keep it reasonably clean by cleaning off the grease and heavy dirt. Don't worry too much about appearance 'cause you're gonna wear it out anyway and it's value is mainly in it's usefullness to it's next owner, maintainence is paramont. If you have invested in something like a CUT that you will use as needed to maintain relatively small acreage then keeping it looking good makes sense since you'll likely never wear it out and it will remain more valuable. My 9N is 60 years old and it dosen't get washed much and I keep it under a roof. My CUT is new and will be kept indoors with my Harley and roadster. I expect the kids will enjoy all of them when I check out.