In my experience the #1 thing that determines how well paint holds up is how often it is waxed and what kind of waxed or protectant is used.
A car that is garaged should get waxed twice a year at a minimum.
Cars that are kept outdoors should be waxed at least every quarter year.
Cars that are kept outdoors need more than the crappy waxes that get sprayed on at automatic car washes. They need high grade synthetic or 100% carnauba waxes that will give them a really tough outer coating to protect the paint and clear coat.
That is likely the issue with my current car. I can't remember the last time I washed it and at this point I'm afraid to I think the dirt is the only thing holding it together. I think it lasted 3 months before I stopped washing it and decided it is an appliance to get me from point a to point b. It got washed a few times after that normally when someone borrowed it they would wash it before returning it.
I'm hoping I will take enough of an interest in the model 3 that I wont let it get to that point but I know myself and figure at most I have 6 months of washing it monthly before I give up.