Hereya go….
I think it's more a combination of factors that will dictate what fails and how often. Like environment of use and what it is used for (towing, pulling,plowing, crawling, etc.).
That said, in a salt environment, coat the underside.
There is no galvanizing used for domestic market WJs so if it is purchased with a clean underside, protect it.
Also,get the simplest HVAC system possible (not the dual zone setup). Forget the auto-dim mirrors and consider the Laredo style side cladding as it will not be painted body color and though it may look faded, will not be scratched paint from regular trail use.
If it has no sunroof, all the better but if it does, maintain it or permanently close it and disconnect the switch. The assembly will break and when it does, the entire headliner has to be replaced and there are no OEM parts available for a reasonable price. Junkyard units have 12 years on them or more and will also break.
For seats, I recommend the leather but the cloth is OK. Next, remove the front seats and either paint, rhinocoat the entire frame or get a spare seat assembly ready to swap in as they often break from poor metal and tough/corrosive environment and poor welds. Yours my never break but many have.
Get a couple of radiators and hose kits with screw-type clamps. The OEM type clamps are not meant for ease of regular service use.
Try to find an all aluminum radiator if you can. One tough trail impact or stray branch and a radiator is done.
Get a couple of extra Speed Sensors and know how to change them.
If it is the 4.0, get a couple of coil rail assemblies as they tend to crack and cause misfires.
Get a couple of fuel filters and swap them every 2 years.
Get an external trans cooler and install it.
Stock up on a high zddp oil like Rotella and use it because the 4.0 has a flat tappet valve train and needs the extra zinc for long life.
Get some grommets for the valve cover as they tend to harden from heat cycling and become brittle.
Get some PCV valves and change them with the fuel filter.
Get both new differential covers with a drain plug on it so you can swap fluid with out having to remove the cover. Same for the transmission cover for that fluid. A single high water crossing may toast your differentials so check the diff vent tubes for being in the right position and located high up on the vehicle or extend them.
Extra windshield wipers and don't forget the rear one.
Get some single piece lug nuts (and a decent tire iron that fits them) with a tall bottle jack. (The oem versions of those items are junk.)
Get a set of spare wheels so you can swap in a new set and even tire wear for long trips and varied conditions.
Get a tire puncture repair kit and a manual tire bead breaker.
Get a couple of water pumps as one may be bad out of the box, both unlikely. 2 thermostats too.
Several tubes of RTV.
Get a good set of Torx sockets, metric sockets, extensions, swivels, spark plug socket, pliers, vice-grips, pry-bar, wrenches and LG/SM screwdrivers.
Get a set of spark plugs & change them every 30K. OEM brand/type is fine.
Get a spare O2 set and know if you have 2 or 3 of them....plus the 02 removal socket and copper anti-seize for the new ones.
Get a soldering gun.
Write Kolak's cellphone number on the headliner in permanent marker.
Get a clockspring as a backup and a steering wheel puller.
Get a high pressure power steering hose as a backup.
Get a set of headlight, signal, reverse and brake bulbs.
Get a spare flasher relay as they are known to fail.
Get a spare fan control relay as they often fail on the 4.0 as the electronic fan ages and draws more amperage.
Get a new electronic fan too and consider the Ford Taurus fan upgrade.
Get the 160Amp Alternator for a Durango of the same year as the original one willdie around 12-13 years of use. OEM is only 136 amps or so…
Get a couple of extra door lock actuators and try to only lock/unlock the door withthe key and not the remote to extend the actuator's life.
If it has the engine mounted fan clutch system, get a spare.
Get a few oil pressure sending units as they fail every 2-3 years.
Air filters, oil filters and a brake bleeder kit is a good idea too.
Get a front driveshaft (OEM style will fail in a few years.) and front CV axles for both wheels.
Get an extra steering stabilizer as that will likely take an impact from rough trails.
Lastly, download the service manual and consider taking me with you.