That you retain till your current ride?
For me is a rear view mirror “See Wing” from my first car till now. That was in 1991 on a Toyota Starlet till now on Skoda Superb.. it been on more than 10 cars since.. it help me see blind spot and save me countless time.. so insecure without it..
The other thing not on first car but fourth car is my number plate.. from 1996 Civic SiR till now.. it is a 1981 ER plate..