Re: Do you switch off your aircon?
Your car will adapt according to your habit.
I never switch off the a/c when switching off the engine. Obviously, it will require more battery charge when starting the engine if the a/c is left on. But the car gets used to this and will push out sufficient battery power to start your car effortlessly. Since this is the case, I believe it is better to train your car (or battery) to handle the stress of starting the engine with the additional a/c load. There has been no undue and premature damage of my a/c or battery in all my years of driving (20+ years).
To share an experience, my uncle, who lives next door, he will meticulously off his a/c b4 switching off his engine everytime. One time, I drove him (using his car - E200) to the airport to catch a flight . Since I did not have the habit to switch off the a/c.... I simply off the engine. When I came back to the car about 1 hour later and tried to start the engine, it would crank but not fully start. It took me a while to figure out to switch off the a/c and ...
....the engine started up immediately. This convinced me that the car adapts to your driving habits.
That being said, in case your car battery is dying (which can be any time without warning).... you would have a better chance of starting your car if your a/c was already off in the first place. Otherwise the initial surge required to start the engine and power up the a/c may deplete the last bit of juice in a dying battery that can no longer self-charge, and you would lose the one opportunity to self-start your car to drive to the nearest workshop for help.
Another point is I do not warm up my car in the morning before driving off. The car will train itself and adapt to this as well. (However I would warm up the car for 1-2 minutes to allow the oil to lubricate the bone-dry engine first.... if it hasn't been driven for a week.)
Take this simple test.... find a friend who has a habit of warming up his car in the morning before driving off.... borrow his car and be the one to start his car one morning and
try to drive off immediately without warming up.... there is a good chance the car will sputter with effort if it drives off or the engine will die trying.... (this seems to be true especially in
older cars that are so used to being warmed up in the morning.)
It is the same logic as the need to clear your exhaust carbon from time to time. Treating your ride too gently may actually be more detrimental to your car in the long run. (just my humble opinion). Peace!