The main cause of engine where is actually starting a cold engine that's when 90 something percent of the wear occurs. Most other things are normal wear and tear unless you pull an awful heavy load

You don't want to go red-lining your engine when it's not warmed up or run it low on oil. Over-revving and reduced oil cause almost all wear inside the engine. Engines are designed to go through so many billions of revolutions before beginning to depart from their tolerances. High revving burns through the wear tolerances faster, but it takes A LOT of over-revving to be noticeable. I let my fuel injected engines run until they come down off the fast idle before starting to drive. There's no reason you can't climb that hill faster than 20 mph and in a higher gear than 1st or 2nd, unless it's a very steep hill. It only takes a few seconds to get the oil circulating through the engine, and as long as you're not climbing said hill in the power band and mashing through your gears like a madman, you're not harming anything going up faster than 20 mph. Let it come down off the fast idle for peace of mind and you'll be good to go.

From my experience,

Running On Dirty Oil - manufacturer often recommend ridiculous change intervals and the owners that listen end run the engine on what is essentially sludge with no lubricating abilities, so during that last 3-4 thousands of miles before the oil change most of the internal wear occurs.

A well known example is the Citroën-BMW-Mini Prince engine (BMW N13, Mini N14/N18, Citroën EP6) often recommend a 12,500 mile (20k km) change interval and those engine became to known as "The service man's dream" due to the sheer amount of issues it had. On the other-hand, if you replace the oil every 6,250 miles (10k km) - you likely won't have any of these problems with this engine through out it's lifetime.

Constantly driving the engine under huge load - won't do it much good either. If the engine doesn't have a well though out cooling system it can even cause the cylinders to deform (like what happens with some Ford Sigma engines). Also I'm not sure but from my understanding on some turbocharged engines with a waste-gate, constantly running them on max boost can weaken the metal (some are built to constantly be under boost like the Ford EcoBoost 1.0L 3 cylinder, But I'm still sure that it doesn't do much good to it's engine). 

And as scotty said, cold starts also cause a lot of wear until your engine gets properly lubricated and gets to optimal operating temperature.

Also, each engine has its specific weak-points. For example on the GM EcoTec you should check the PCV membranes because those can cause damage due to high pressure in the crankcase even before 60k miles., Some engines like the Mazda L-series (although it's generally a great engine - it has it's quirks) requires you to avoid short drives as on these engines that what causes the most wear to it's piston rings that are already are of questionable quality, and so on...

But nowadays, your automatic transmission is likely to fail way before your engine will start to show any signs of wear on most modern well-built cars.

Also on with the Land Cruiser it's important to know that there's the Landcruiser J200 (2007 - 2021), J150 (2009-new), and J300 (2021-new) and they're all drastically different cars.

The J200 diesel is a 4.5L V8 that lasts hundreds of thousands of miles, while the J150 diesel 3.0 I4 had piston issues for the first decade of that engine's production (first introduced on the 2001 Toyota Hilux).

Also the new J300 land cruiser is going to have some new V6 diesel (there's very little info on it) or a 3.4L V6 Lexus LS500 Twin Turbo Dynamic Force engine (that's also new and is based on space-age tech) - Although I'd just recommend to get a 4.0L petrol or an older model with the 4.5L V8 diesel could be even better.

Usually I'd recommend the J150 with the 2.7L petrol 4 cylinder as it's extremely reliable and it's punchy enough (0-60mph in about 11.5 secs) but it's really not good at towing as it has under 250NM, that's about as much as a mid spec 100 horsepower 2001 Skoda Fabia TDI 🤣...

Hi.

Always have clean engine oil. Change it regularly and use a good quality one. I never go beyond 5,000 miles between changes. Using the correct viscosity is important. Not too thick a one. Scotty mentions this in one of his videos.

What vehicle are you using?

The Toyota Land Cruiser is a superb tow vehicle. About as reliable as you can get too. Is it possible to get the Diesel engine one where you are? These are capable of starship type mileage.