Like the Inspector said.
Japan does encourage its farmers to trade in, through its tax laws. A used tractor brought to the US from Japan can have a lot of life in it.
Yanmar-Japan does not have a rebuild facility. (They are good about supplying needed parts through their dealers for tractors that are still being used in that tractor's intended market.)
However if the used Yanmar then went to Vietnam for a second life, it may have been run until dead. There wouldn't be any reason to take it out of service while it is still productive. VN is one of the poorest countries on earth. I doubt it has farmer subsidies as described. Certainly not a new tractor every 5 years!
There have been many posts here describing VN rebuilt tractors. The most striking characteristic is that NOT A SINGLE PART SOURCED FROM YANMAR-JAPAN is used in the rebuild project. I have an image in my mind of rows of kids each attacking a block of metal using a file, but no measuring instruments, manufacturing the parts used in a VN rebuild. The end product is not the same thing as a used Japanese tractor.
Yanmar's basic quality is so good that many, most, used Yanmars are an excellent buy. They should run for many years with adequate maintenance. You probably have read that Yanmar built John Deere's small tractors for many years.
However the VN rebuilts are more of a gamble. Many people have good luck, some don't. There have been quite a few horror stories posted here about Yanmars with museum-quality paint represented as a couple of years old, which in fact are 30 years old and cobbled together out of mismatching and unidentifiaible parts.
My point: choose your dealer wisely. The legitimate importers sell an excellent product and stand behind it.
According to the dealer, these machines are from Viet Nam farmers who are given new tractors every five years
RUN!!!
