I had it done on my brand new Kia Stinger GT2, while it might not require a full service paint correction with cutting/polishing it still needed a minor one to take out little imperfections found during the shipping and initial wash the dealer did. I had Ceramic Pro applied with their Gold Package, it carries a claimed "Lifetime Warranty" but is expected to last 5-7 years. I already don't use automatic car washes and it is mostly garage kept so it was a easy investment decision on my part. I paid $1200 which included the paint correction, coating, and taxes/fees. Maintaining the warranty is a yearly visit to their shop for inspection and full detail ($120), paint is still pristine and water beads off like a freshly waxed car.
the DIY options won't give you the results and as bbf said it could be more damaging. Wife's used BMW had a diy job done and they left the coating on too long prior to wiping it off in spots. when washed it left a rainbow sheen across the black car. Only fix was a very serious cut/polish to restore the factory finish. We just had her car ppf wrapped with DYNOmatte which was pretty pricy but cheaper than buying new already matte painted.