See Item no. 2 below.
Three things will cause unnecessary wear on an engine:
1. Not driving it often enough. When an engine sits the oil drains into the pan and off of the moving parts. 90% of engine wear occurs when it is turned on because the moving parts are unlubricated until the oil pump starts a pumpin. So it stands to reason that the longer between starts the more wear occurs. Engines that get the most miles on them are police, ambulance, transportation, and service type vehicles. They run constantly. The shorter the duration that an engine is turned off between starts, the more miles you will get on it.
2. Not driving an engine long enough when it is run. One of the by-products of the internal combustion process is H20 (water). Ever notice the puddle of water under the exhaust pipe when an engine is still running cold? When an engine is not run long enough to reach normal operating temperature the water doesn’t evaporate. It mixes with the oil and becomes...you guessed it, sludge. Sludge is a bad thing.
3. Dirty oil. No elaboration required.
One of the worst things one can do is buy a low mileage used car from a little old lady for any or all of the reasons mentioned above.
Unfortunately we can’t always know the history of the previous owner of a used car or we’d all opt for one that was driven 5 miles each way to work every day and somewhere on weekends. So, the next best thing is to get one that has a reputation for being dependable. Toyota vehicles answer that description. I’ve had most of ‘em and the trucks are no exception.
A high mileage engine is not necessarily a bad thing. One reason people use “freeway miles” as a selling point is because of no. 2 above and because of the logical minimum wear that occurs on tires, steering, suspension, cooling, exhaust (remember the H20) and braking systems.