If you haven't bought your tractor yet, here are a few things to consider.  Feel free to skip any if they're too obvious or not important to you or whatever.

Brand considerations aside, pretty much any utility tractor built since the mid 50s or so could be a good all-purpose chore tractor.   Tractors from the 40s, 30s, and even 20s can also still perform a lot of hard work, but you would likely be limited to pulling something hooked to the drawbar, or using the power takeoff or belt pulley to power a piece of equipment.  Newer tractors are likely to have more advanced and more flexible systems--so consider the type of work you plan to do and the types of implements you'd like to use, and then look for a tractor that will meet those needs. 

Modern convenience features to look for are live power takeoff, live hydraulics, a standard three-point hitch, and one or more hydraulic outlets for implement-mounted hydraulic cylinders.  If you plan to use a tractor with a front-end loader, power steering would make operating it a lot easier. 

I'd expect a good tractor with these features to cost at least $2500, more for newer models or more popular brands.  To get a feel for prices of a particular machine, browse www.TractorHouse.com or search eBay auctions for the model you're interested in, or even just for "farm tractor."  There's also a farm equipment "Blue Book" called the Hotline Farm Equipment Guide, available from the Heartland Communications Group at (800) 673-4763. 

When you're evaluating a specific tractor and you've gotten past looking at the features, try to get a feel for how comfortable a machine it will be to operate.  Can you get on and off easily?  Can you comfortably reach and operate all the controls? What will it be like after an hour in the seat, when you still have another hour or two to go?  If you have hilly terrain, will you be able to brace yourself comfortably to resist the pull of gravity when working on a hillside? 

If you're buying a tractor to use rather than as a repair project, and you've decided on a particular type or model of tractor, buy the very best example you can find.  It will almost certainly be less expensive in the long run than buying one that needs lots of repairs, even if they're little ones and you do the work yourself.

Once you have the tractor you should at a minimum also buy an operator's manual for it, and parts and services manuals if you plan to do any work on it yourself.  I've found them to be a great help in simply understanding how the machine is put together and how it's supposed to work, even if I don't do the heavy repairs myself.  Original manuals can often be found on eBay, by searching for the make and model name of a particular tractor and then browsing the results.  You can also look for manuals at tractor dealerships or try the following sources: 

• Binder Books, for high-quality reproductions of manuals for old International Harvester tractors
• Jensales, for photocopy reprints of manuals for a huge variety of old equipment.
• John Deere Distribution Services, for manuals on any John Deere tractor.  Call (800) 522-7448, or write to them at 5440 Corporate Park Drive at I-74 and 53rd Street, Davenport, IA 52807. 

There are three basic types of wheeled tractors: "row-crops," "standard-treads," and "utilities."  Row-crops (like this Super M Farmall) have higher centers of gravity than the others, since they're designed to be high enough to drive over young corn and soybeans while cultivating between the rows.  (Hence the "row-crop" designation).  They also have adjustable wheel spacing, to allow for different spacing of the crop rows.  Many came with a tricycle-style narrow front end, but an adjustable wide front end was usually available as an option.  Row-crop tractors built before the early to mid-1950s likely don't have much hydraulic capacity or a 3-point hitch; those built from the late 50s on up probably do.

(There are also "high-crop" tractors with even higher clearance than row-crops, designed for working with tobacco or other tall crops.  Other than special front and rear axles and wheels, these tractors are usually very similar to the row-crop versions). 

Big standard-tread tractors are also known as "wheatlands," since they were designed for grain-producing regions where the big task was plowing those enormous wheatfields rather than cultivating corn or beans.  They're usually lower to the ground than row-crops, and the wheel spacing isn't adjustable (hence "standard-tread").  They don't often have three-point hitches, since most of their work was in pulling big heavy plows and combines and such. 

Utility tractors, as the name implies, are great all-purpose machines.  They have low centers of gravity and wide front ends like standard-tread tractors, but with adjustable wheel spacing and 3-point hitches.  For an all-around chore tractor, it's the type to have.

"Live power" or "live hydraulics" means the power takeoff shaft or the hydraulics are not affected by the transmission clutch, so you can start or stop the pto or raise and lower the hydraulics whenever you want, regardless of whether the tractor is moving or in gear or the clutch is in or whatever.  That's a really, really nice feature.  Without it you can't start a mower running before you begin forward motion of the tractor, for example, or the hydraulic pump stops every time you push in the clutch.  Tractors built since the mid-50s or so are likely to have live power and hydraulics; older tractors typically will not. 

(If you brushhog with a tractor that does not have live pto, by all means install an over-running clutch on the pto shaft before hooking up the brushhog.  An over-running clutch is a simple ratchet kind of thing that costs about $60 at a farm-supply store or tractor dealer, and that only transmits torque in one direction.  That allows the tractor to drive the brushhog, but prevents the huge momentum of those spinning blades from driving the tractor forward even after you push in the transmission clutch.  Being unable to stop a heavy machine with sharp rotating blades is a bad thing). 

A standard three-point hitch lets you quickly hook up to a huge variety of implements regardless of the manufacturer.  Most tractors built since the late 50s have a 3-point hitch.  (Before that they had only a drawbar, or a hydraulic hitch that only fit implements made by the same company as the tractor.  A guy named Harry Ferguson invented the 3-point hitch and went into partnership with Henry Ford, so Fords had it before anyone else.  It went off-patent in the 50s sometime, and all the other manufacturers eventually adopted it). 

As an option to buying a tractor that was built with these features, you might consider buying an older model and then upgrading it with after-market equipment.  A live hydraulic pump and a three-point-hitch kit can be installed on a Farmall H or M, for example, for maybe a thousand dollars worth of parts.  The resulting system would not have automatic load and depth control, and so wouldn't be as convenient as a newer system would for jobs like plowing or cultivating with 3-point mounted implements, but it would work reasonably well for raising and lowering a 3-point disk, brushhog, or rear blade.  Since those bigger, older tractors are often much cheaper than smaller, more modern utility tractors, it may be a good investment overall.  Live power take-off is harder to retrofit, but even that was done on some of the old Farmalls.  See the discussion on my Notes About the Farmall M page for more information about aftermarket 3-point hitches and live power takeoff clutches. 

The best rollover protection advice I can give is to buy a tractor with a low center of gravity, and then operate it safely (avoid driving up or across steep slopes, slow down when turning, never turn sharply with a raised front end loader, and never hitch anything to the tractor other than at the drawbar).

In terms of the tractor's basic geometry and configuration, the biggest factors in determining its resistance to rolling over are the center of gravity and the rear wheel spacing.  The lower the center of gravity, and the wider the rear wheel spacing, the less likely it is to roll over.

The configuration of the front end matters, but not nearly as much as the center of gravity and the rear wheel spacing.  A "wide front end" is not rigid like the tractor's rear axle--it's designed to rotate about the long axis of the tractor, up to a point, so that the tractor can drive over uneven terrain and still keep both front wheels on the ground.  Until a tractor tips far enough that the wide front end rotates all the way to its stopping point, the wide front end doesn't provide any more resistance to overturning than does a narrow tricycle configuration.  My point isn't that narrow front ends are safe--rather, it's that wide front ends don't make a high-center-of-gravity tractor safe either.  If you're buying a tractor to use on hilly terrain, choose a utility tractor for its lower center of gravity.

If rollover is a real concern for you, consider buying a tractor with a professionally-installed rollover protection system (ROPS).  That pretty much rules out any tractor built before the early 60s or so, when ROPS first became available and when tractors began to be designed for them. 

Although it's possible to weld or bolt a roll cage onto just about anything, I'd be very cautious about doing so with a pre-sixties tractor, or buying any tractor that has a home-built cage or roll bar mounted on it.  That's because it won't be much use until you really need it, and at that point it or the tractor it's mounted on might behave in unexpected ways.  A real rollover protection system is just that--a system, designed to act as a unit with the frame of the tractor and tested under lots of load and temperature conditions, and I recommend leaving that challenge to the manufacturers. 

That's not to say you can't have an ROPS added to a tractor that didn't come from the factory with one.  Retrofit kits are becoming available for many tractors that weren't originally built with a rollover protection system, but they're still limited to tractors from the 60s or later.  In February 1997, John Deere announced:   

For more details, check with a tractor dealer or try the following sources: 

• The National Ag Safety Database
• The National Farm Medicine Center Guide to Tractor ROPS

If a small utility tractor sounds like the right thing to buy, Ford and Ferguson pretty much invented them and made most of them for a long time.  The original ones--the Ford-Ferguson 9N (introduced in 1939), the 2N (1942) and the 8N (1948)--had three-point hitches when no other tractors did, which made them very popular.  There are still zillions of them around, and they're pretty capable.  But they don't have live pto or live hydraulics. 

The replacement for the 8N was the NAA, otherwise known as the "Jubilee."  (I think it was introduced on Ford's 50th anniversary, or something like that, so it had a "Golden Jubilee" badge on the hood).  Live hydraulics were standard and live pto was optional--so this'd be a great tractor if you find one with the live pto.  After the NAA Ford switched to three-digit model numbers, like "600" and "501" and many others.  Any of them would be great, but you'd probably still have to check on the live pto--I don't know when that became standard rather than an option.

Ford and Ferguson went their separate ways after jointly producing the 9N, 2N, and 8N, and Ferguson eventually merged with Massey-Harris, so there are Ferguson and Massey-Ferguson tractors that are comparable to those later Fords.  I don't know the specifics, but any of them would be very capable. 

An Oliver Super 55 or its successor, the 550, would also be a great utility tractor.  They were Oliver's deliberate attempt to compete with Ford in the utility tractor market, and the 550 was made for a lot of years--like 1958 through 75, or something like that.  Very good little tractors, with the 3-point hitch, live pto, and live hydraulics all standard.  Repair parts for Olivers can be harder to come by than parts for other brands, so check out the farm equipment dealerships and salvage yards in your area before buying one. 

An Allis-Chalmers D-15 is another good candidate for an all-purpose chore tractor.  It doesn't really have live pto, but it has a "Power Director" clutch that's about as good.  It's a high/neutral/low-range hand clutch that affects motion of the tractor but not the pto--so with the hand clutch in neutral, you can put the tractor in gear, engage the pto, let out the normal foot-operated transmission clutch, and the brushhog gets up to speed.  Then when you're ready, you engage the hand clutch and the tractor starts to move.  Same concept if you're going through thick brush and you want to slow down or stop without stopping the brushhog, or if you're baling hay and need to let the baler catch up with a thick spot in the windrow--just put the hand clutch in neutral. 

We didn't have any hydraulic implements when my dad had a D-15, so I don't know if the hydraulics were live or not, but I suspect they worked just the same as the pto.  The D-series Allis tractors also typically have Allis's proprietary "Snap Coupler" two-point hitch, and 3-point conversion kits are available. 

There are of course also many great choices among newer machines, those from the 60s or 70s, which would still have a nice "classic tractor" feel.  A Ford 2000 or 3000 would be hard to beat.  Same for a John Deere 2020, and no doubt many others.

All that said, there are lots of reasons to buy a specific brand or type of tractor that have nothing to do with practical considerations.  You may love that two-cylinder sound of the old John Deeres, or you may want a brand or model that has some historical or sentimental value to you. 

I bought a 1953 International Harvester Super M Farmall, which didn't have live pto or a 3-point hitch (or any other hydraulic hitch, for that matter), and it had a high center of gravity.   I bought it because I liked it, and because it reminded me of a life my dad and granddad told me about but which I never really lived, and because it worked great for raking hay, pulling a wagon loaded with fence-repair tools or manure or kids (not all at the same time), and for most other routine chores.  I eventually sold it to make room for a bigger, more modern tractor (John Deere 3020), but I sold that too since I didn't really have any use for it.  Some years later I bought another Farmall M, just to have one and to be able to tinker with it in the garage, and to daydream about someday moving back to the country and putting it to work.

Thanks for the opportunity, and best of luck with your search.  I hope this can be helpful.