I've looked at used too but since Tesla's hold their value so well it makes no sense. Ppl are asking like $45000 for a few year old model 3. Which is basically what they paid new minus the discount.
And you have to figure out financing.
Tesla offered me 2.4% on a 96 mth loan. It doesn't make sense for me to buy used unless I take money from a home line of credit at lower than 2.4%
Also for model 3 and y they introduce heat pumps which gives you a more efficient hvac so you get more range than older models. 21 is a refresh year.