A system that works for me is to take machines in for an annual inspection and software update, but not to authorize fixing most of what is found. They almost always find something I would have missed, and I get the benefit of the software updates as well. I then bring machines home and work through the list I have been given. I used my machines for my livelihood, and breakdowns cost TIME, and time is money. So for a couple of hundred a machine, I have them thoroughly gone over, and then I do most of the work. A good, inexpensive compromise that assures me the season will go smoothly. Once in maybe every third year or so they find something needing immediate attention that I don't want to tackle, and then I might spend $700-1000--but I can make that back up in a day's work, AND my machine is good to go for all season. I would never spend my money on paying for fluid changes, case drain filter work, new belts/hoses, replacing belt tensioners, alternators, etc, etc. I can do those things myself.