Really no reason not to. Tractors last forever if you take care of them. Old John Deere tractors like the 4020 (late 60s, early 70s) and the 4440 (late 70s, early 80s) still sell for as much or more than they did new and there are thousands of them still in use every day. I still have a 1976 4430 with a dozer blade on it and it's perfectly reliable to be our snow moving machine. It was $23k new and I could probably sell it for $20k now even though I'm 44 and there's a picture of me as a baby riding in it with my Dad.