4 months for my 2016 Model S. Most of this time (all but 2 weeks, I think) was waiting for airbag related parts. Missed the entire summer last year -- accident in May, got the car back in September. Suffered crappy rental cars.
This was a lease, and my wife and I did not get another after the lease return. Definitely makes me hesitant about getting another.
Took 5 months to get my 2016 Model S back after I was hit.
I loved this car, but frankly I never again want to deal with them. Cancelled my Model 3 order, and now tell everyone that asks me about the car to stay away.