Good maintenance is your best defense against unexpected break downs. ...Or rather, you should probably expect to break down if you ignore maintenance, and it usually happens at the most inconvenient time and place. Consider if something is predictable it's preventable, and mechanical objects have very predictable tendencies and outcomes. Regular fluid and filter changes along with mechanic inspections will reveal most major problems long before they happen. This gives you time to pre-plan repairs and hopefully prevent a break down while on the road. Engine and transmission are probably the two biggest things that could kill your rig and pocket book, everything else is nickel/dime in comparison. Engines... as long as they don't overheat or get low on fluids will generally have a slow steady decline. Let an engine run low on oil or overheat just one time and it goes bad in a hurry. How do you prevent engine damage? Check and keep proper level of oil in the engine and change oil/filter at regular intervals. If the engine starts running odd, or the 'check engine' light comes on have it checked and repaired right away. How do you prevent an overheat? Check and keep fresh coolant to prevent corrosion and radiator leaks, make sure hoses are in good shape, keep good belts on the engine, have the mechanic check the water pump and fan clutch for excessive play. Same thing with transmissions, changing fluid just once can generally double the life/mileage of a transmission, but I'd recommend fluid about every 30-35k miles for severe use. If the fluid smells burnt, darkens quickly after a change, slow going into gear on cold mornings, or shifting odd that could be an indication that its starting to slip. A mechanic inspection can usually estimate how long before needing brakes or suspension repairs and you can pre-plan those repairs. If brake linings are low but not completely gone you can baby it, choose to avoid remote areas, long drives, or hilly routes until you have funds to fix it. Batteries usually have a date decal on top and depending on the brand and model can last anywhere from 2 to 5 years, knowing that you'll have a rough idea about when it needs replaced. Cold weather and using a start battery for the house is hard on batteries. Usually a battery will give a slow crank or two before it lets you know it's time is up. If you need to push battery life to the limits, keep some jumper cables handy and know how to use them. The things that go out unexpectedly are tires (road damage or age). There are date codes stamped into the tire sidewalls; car tires generally last about 7 years but trucks/vans/rv's need replaced at 4-5 years because of heavy loads. You can squeak by on an older tire or even a used tire if need be, just keep them aired, drive slower, have a spare, and be ready for it to peel a tread. Aside from road debris, low air pressure is the number one cause of premature tire failure, especially on hot days. If you can at least learn how to check and top off the fluids, air the tires, and keep up on maintenance, you'll be doing more to help yourself than most folks...