So this is my used tractor. It's a circa-1993 Kubota 9580. At 100 hp it's got a lot out power, and with 4wd and a shuttle transmission, it's pretty handy around the farm. I paid $16,000 for it, and so far I've spent around $1,000 maintaining it. That's the drawback to used equipment -- you have to fix it.
The other issue with used equipment is that you often don't know the maintenance that was done. So I look at what I'm going to buy carefully, but you're really limited in what you can know. So my routine for buying equipment is to do all of the maintenance that might reasonably be due.
Oil & filter change, hydraulic fluid & filter change, fuel filter change, greasing all fittings (that was a fun 4 hours, let me tell you!), checking the toe-in of the front tires, and so on. With this tractor I also had to mount the drivers side door and rear glass window on the cab; I got the glass as part of the deal, but had to buy the various hinges and so on from kubota (for !!!$500!!! -- are they gold plated? yeesh!) and mount the glass.
This is the reason for todays maintenance break; a 12" gash in the front tire. So the tire itself is $620, and you have to wait a week or so for it to get here. So while the tractor is idle, might as well do a maintenance day on it. Fix the light on the dash that burned out. Check and diagnose why the air conditioner doesn't work (you have to remove half the tractor to replace the fan belt that is missing for the air conditioner-- joy!) and get the various lights working. While you're at it, might as well blow the radiator clean, change the air filter, replace the other belts in the engine compartment that look fine, but hey, you're there anyways, right? and finally replace the hour meter so that you can be more precise in your future maintenance. The hour meter costs $320, by the way.
My experience has been like this for most of the used equipment that I've bought. You either pay the price for a new, or you end up paying a very similar amount in maintenance. The advantage with new is that you know when the payment is due. With a used tractor it pretty much decides when a payment is due.
So this months tractor payment:
Front tire: $620 + $22 mounting fee
New hour meter: $320
Bulbs and lenses for lights: $15
New fan belts: $55
New antifreeze, oil, hydraulic: $120
Air conditioner charging: $65
Plus 2 days of labor to take it all apart, and put it all back together.