I'm on the opposite path. I used to add it to all my cars...Porche's , MB's, McLaren, etc. It seemed critical to me. Then 6 months later I'd give away $6000-$7000 worth of PPF and get basically no return on it. Then with my pre-refresh SLR I thought well, screw it, I'm not doing it. I had some chips and whatnot, but it certainly did not hurt the resale value of the car and if I didn't inspect it super closely then I'd never even notice. I've probably, no exaggeration, given away $30k+ of PPF over the last 6-7 years. That's a LOT of paintwork that could have been done if I needed to.
Now with my Plaid I skipped it too. I'm 7000 miles in so it's too late. The car looks fine. Yep, there's some chips and whatnot, but at this point, whatever. It doesn't hurt that I own a touch up paint company, so I'll use it to make some videos too.