I have to admit I never consider depreciation with any car purchase, When I'm ready to change which can be from around 2 years to 4 years with a car I seem to start taking an interest on what's on the market, what excites me and then read everything i can about the car.
Go to see the car, test drive it and then make the decision to purchase - only then do i ascertain what my trade in would be - though more recently, the last few years I have autotrader'd my car to see what the market is supporting - so i do have a rough idea.
All my life i have lost money on cars but don't see it as wasted because i enjoyed every single one of them - and once i have them they are machine polished and maintained to within an inch of their life, I love detailing and having a car looking brand new (hate dirty cars)
The M3P was not a typical purchase as i didn't test drive or see it beforehand - never even been in any Tesla either - but I so wanted it, so during the lockdown I did the deal over the phone - and my trade in.
Come the time when I'm ready to change again - and only then will I discover just how much depreciation I will suffer, but what i do know is whatever that is will just be viewed as the cost of having the pleasure of owning it - and do it all again with my next choice.
My car will always be very low mileage too as I'm retired, currently a tad under two years old and 6300 miles, I suspect another two to three years the mileage will still be under 12K - and the car immaculate.
The current climate is quite unusual as my car is fetching more now than i paid for it - about £3K more - never experienced that before, but i suspect by mid to late this year things will be normalising. None of us can predict how batteries will hold up and degradation, what's new and tempting/leading the market, long term ownership foibles and how all of that will affect desire in new BEV purchasers moving away from ICE.
I for one am happy with my car, love it and not going to give it a second thought where the value is in another few years.