I am torn here... i guess i can see your point if you get through a lot of cars.
but i am 48 years old and currently only on my 7th car, and 3 of those ran concurrently
2 of them i only got rid of because were written off , one of them my wife took in our divorce settlement and one of them was a 2 seater that i didnt want to sell but had to
For those who keep their cars for a long time, it kind of doesnt matter how much it drops by, if the car is worth £25K to you now and ticks all the boxes you need it to tick then, maybe the answer is to buy then just not look at prices again.
I get it tho, my car depreciated 9k in 7 months despite me buying it 2.5 years old at half price and that does sting a bit.............. but ultimately the car was worth to me what i paid for it at the time, and the car has not changed just because its price has dropped - it just means someone else gets an even better deal than i did.
also consider, the only reason the cars are so cheap is because of supply and demand. there is currently a LOT of similar cars at end of lease flooding the market. presumably even if you do decide to sell and the car has dropped a bit, other cars around it will also have dropped, so even if you do change your car because you are bored and want a change, it means the car you are looking to buy will also be cheaper as well.
I always go into buying a car with the idea that it will be worth next to nothing when i get rid. Anything i get for my cars when i sell is a bonus.