Small time farmers are not trying to save money so much as time. When you are in the middle of nowhere with a broken part no amount of money can get you back in the field in 20 minutes (if the welder is sitting by the phone waiting for your call he can just barely get there in that time, but he hasn't looked at the part yet). 1 minute with your own welder and you have a repair that will let you limp to the end of the busy season where you can decide if it is good enough or you need to repair it right.