What is stressful and wears down a car?

[JordaanDMC-12]

Okay, did a search, and know that most of these answers are scattered through many different threads, so I figure why not put them all in one. I was reading some articles today about high mileage cars and things of that nature, and it got me thinking about how you make a vehicle last and last and last.

Changing all the parts will keep any vehicle going forever, but what measures can one take to assure that the wear on these parts is at a minimum? Is having a car that can do 2.7 million miles (with minimal engine work) just luck?

What is most stressful on an engine? What "wears it down" and causes premature engine failure? And what steps can be taken to prevent that stress? You figure city driving, driving on lots of steep hills, and high speed driving? I read somewhere that an engine is "content" driving about 65mph in 70 degree weather and with solely the driver. I had a friend back in high school that was always flooring his car and revving the engine pretty good, driving fast and always trying to pass people. I was always told this type of behavior was very hard on an engine and that light driving was much more healthy.

But you hear that light driving is also an "annoyance" to the engine since it can't "clean it self out" with occasional high revving. So if you're driving on a long 10+ hour drive, is it stressful on the engine to be driving 80mph rather than 65? Will driving at lower speeds help with engine longevity? What are some measures you can take while driving your car, to ease the stress that is put on the engine?

Everyone here wants theirs cars to last as long as possible, so what maintenance do y'all do to keep them in the best shape? How often should brake, power steering, and coolant fluids be flushed? I was told that transmission fluid should be changed out every 10,000 miles and was told from another source every 30,000 miles. You hear that many problems with electronics is due to the wires casing cracking and exposing the contents cause shorts and numerous gremlins that have us pulling our hair out. Does anyone use sprays and dressings to help with the moisture of the wiring harness and plastics that protect sensors and delicate electronics?

Rust is also a big factor for many of you, and I don't have much advice in this department, so what are some techniques many of you do to prevent rust and prepare for the upcoming season changes? How often should differential fluid be changed and do chassis ever need re-greasing? I know there are many things I didn't cover but I don't want to make this too long of a novel. Anyone, please feel free to add to it.

So overall:

1.) What is stressful on an engine?
2.) What essential maintenance should be done and how often?
3.) What are the "small" things you all do you feel will keep it going longer?
4.) What driving techniques are easier on an engine, if any?
and lastly In your personal opinion, what would it take for YOUR car to make it to a million miles? (Gas or Diesel)

Also, I know this information is/will be redundant but i'd love to get people's opinons, little tricks people do to keep things going, myths and reality, debating! haha j/k Just information.