If you buy new the minute you drive it off the forecourt you have lost a few thousand pounds already as nobody will buy a "second hand" car for anything near what you paid for it, even if it is virtually new.
Years ago cars were less reliable and so it may have made sense to buy new, but nowadays cars are generally very reliable and you can get 10 years out of most cars.
So if you buy one 2 or 3 years old you can expect to get 7 or 8 years out of it if you want to keep it that long.