They're required to designate model years and have since 2019 IIRC. I can't recall the exact reason off hand.Tesla makes continuous changes. They do not have model years.
To answer your question posed in the thread title: Whenever the factory starts shipping out cars that have an "M" in the 10th position of the VIN.I know they are the same but I have a 2019 and am ordering another, when I go to sell would be better to have a 1 yr newer car.
They've always been required to designate model years, that's federal law and it's part of the VIN.
What changed last year was prior to late 2019, the model year was 100% based on the date the car was built (unlike traditional car makers).
Car was build Dec 31, 2018? It's a 2018.
Oct 2019 that changed and they began labeling cars built then (and onward) as 2020s.
(some suggested this might be due to delays in getting cars to Europe which rolled out last year and that someone in the EU might be update they were taking delivery of a 2019 when it was already 2020- no idea if that's the real reason though).
It's presumed they'll stick to this going forward and 2021s will be October 2020 and onward production, but I don't know we have anything confirming that until it happens.
It clearly does make a difference. If you trade the car back to Tesla it makes a difference how much they give you, if you sell it outright, if you are a bank financing the car it does too. On a depreciating asset like a car the newer the year the better.I think the model year does make a difference when it comes to resell value, please correct me if I am wrong though