PPF threads here are like oil threads for ICE motors. Let's start with the end; YMMV.
I am on my 4th Tesla in 2 years. The pain sucks for my Fremont built cars. Full stop. It sucks.
Of my 4 Teslas, one had no PPF, one had partial and two with full. The one without PPF (M3 LR), had its nose looking like it was sandblasted after 2k miles. The other one driving on the same roads, but typically at higher speeds, with PPF looked new. No rocks punched through the PPF.
I was lucky enough that someone drove across the nose of the M3 LR. So I got the entire nose repainted. SInce the car was already damaged, I didn't bother getting PPF on it and the paint needed to cure. Guess what? In the 18 months since the nose was replaced and painted, the car looks amazingly well. The Tesla-approved body shop did a much better job painting car than the factory did and has held up MUCH better.
I got some chipping behind the wheels until I got mudflaps on the M3. I don't worry that much about it at this point. It was sort of our beater car anyway. Hate to use that term but that is what it basically is.
On my MS Plaid, I switched from Xpel which had been on my other cars to STEK. This was clearly an improvement I can see. The hydrophobicity is better, it is clearer and I think a better film overall. The hydrophobicity as well as shine really makes the stock white paint pop. I also have to park my car where there are tree droppings at times. In one day the 3 was stained bad enough I had to spend hour taking care of it. With the Plaid, I just washed all the crap off when I got home pretty easily.
The PPF has saved all the chipping on my rear quarters and behind the wheels. All the power the Plaid lays down means it can through up a lot of road debris when hard on it. At the end of the day, it makes it easier to maintain my car and it looks cleaner. The lack of chipping is a huge plus to me. Not to mention, any paintwork will typically further devalue the car. So I have to repaint a section, I am going to get hit with even more depreciation. If the paint as thin as it was on my Y, I'd have even more to worry about.
For me the real benefit is in the garage. My wife walks past the car carrying stuff to hers most days. I can't tell you how many times she's grazed the car with her purse or other stuff she is carrying. The stock paint would have been chewed up pretty badly by now. With the PPF, it is holding up great. At times I am amazed by what the self healing has done by just leaving it in the sun or pouring warm water on it.
If you have a white car, don't do a strip of anything, do an entire panel or you will have a dirt seam that is annoying. I am glad I did my S and glad I didn't do my 3. Don't both ceramic coating the PPF, at least not for the first 18 months or so. I did do all my glass on the S's and Y and will do my 3 soon.