I carry more than most. Grew up on the farm, fixing everything and being self sufficient. That carries over to everything I do.
In the bed on the bottom row I have two Packouts for supplies and spare parts, and two ice chests.
One of the Packouts holds: two bottle of Slime, tire plug kit, Colby emergency valve stems, Glue Tread Kit, a Sidewall slug, a Gambit emergency axle replacement, and a funnel. The other one holds spare ball joints, a spare brake line, bolts, Gorilla duct tape, several types of glue, digital multimeter, test light, fuses, jumper wires, spare wire, crimp on connector and wire nuts. One of the ice chests hold drinks, the other lunch meat, cheese, other cold food. One Packout on top is for food like chips, snacks that don't need refrigeration. The second holds my Dewalt saw (same battery as my impact so I always have two that way).
In the floorboard of the back seat I have two more Packouts. One contains tools, the other my VIAR air compressor, and hoses, digital tire pressure gauge. The air compressor plugs into a 2 pin SAE power socket on the plastic behind the seat. The air hose will easily reach all tires.
I have zippered bags sitting across the rear seat. They contain a spare winch, winch power cord and wired remote (winch gets power from binding posts on back of driver's seat). Winch can connect to the rear hitch to pull me backwards or with a strap I can winch from the side to pull the machine back over. I also carry a survival bag with firestarter, water purification, small propane stove, etc. Another set of bags (one for GF and one for me) they contain extra coats, hats, gloves and rain suits.
Under the rear sets is a fire extinguisher, scissor jack and 4 steel rods (think large nails) that I can drive into the ground for a winching point if necessary.
I have a Baofeng Dual Band 50W Mobile Radio programmed with all emergency freqs in the areas that we ride, as well as ham repeaters (licensed ham here) and all Sheriff's frequencies. We have been carrying a Garmin Inreach satellite messenger but now carry a Starlink mini for emergency communications. Once AST Spacemobile gets their birds in the air I will add their satellite messenging to both of our phones. I tried Tmobile but they claim our phones aren't compatible- more than likely they just want me to switch over which ain't happening.
I don't carry axles on the trail, they stay in the trailer. The spare tire stays in the trailer as well. Between all of the stuff I carry I should be able to fix a flat, if not I have beadlocks so will just drive home slow. I can lay the spare on top of the Packouts and strap it down for a long trip but so far haven't. We have had to use gas from one Rotopax so I do recommend carrying fuel. We typically get 10-12 mpg.
I think that's most of it!!! We ride alone a lot in Colorado so we come prepared.
My advice is to buy some spare parts,- ball joints, extra shock bolts, A arm bolts, etc. Then get in your garage and find what tools it takes to replace these parts. Then carry those parts with you.
Also no use carrying axles on the trail if you don't carry a jack and the tools to change it. Most don't put anti-seize on their axles and can't get them out anyway with out an ordeal. Every machine I get gets anti seize put on the splines before the first ride.