When I recently bought a used Mustang before it had been put through the reconditioning that trade-ins go through to make most of them look so new these days, I had my doubts that the salesman was right about the miracle their reconditioning guy was going to perform the next time he came around, so I did a little research. He either used "Forever Black" or a product like it to re-dye the black plastic parts. It is sold to professional auto detailers, and only dyes porous items, so you don't have to worry about messing up your paint with it. When I picked up my car, it looked like a different vehicle. The black was black again, and, of course, he had paintlessly removed dents and sanded the cloudiness out of the headlamp covers as well. I found Forever Black on Ebay and immediately ordered a bottle for my ST, as it was also showing fade after only 25k miles. It comes in a bottle the size and shape of a liquid shoe polish bottle. It is easy to apply and fast to dry. I have had it on long enough to know for certain that it does not "rain" off or come off in the wash like mere protectants do, and because it is a dye, if you get it on your clothes or somehow get it inside your car, it's going to stay there for good. I applied about four coats to my mirrors, the plastic tray where the windshield wipers sit, the tailgate handle, the black knobby pads on the back bumper, and the non-metal areas around my windows. It is supposed to last at least as long as the original black did. It says you can do two whole cars with it. I had enough left over to do my parents' Sunfire, then I added more coats to my Mustang, and I still have at least half a bottle. I got plenty on my paint, but if it was still wet, I wiped it off, and if it had dried, I waxed it off. It cost me about $17 to get it here, but it is well worth it. It comes in gray, too, and when my cladding looks bad all over instead of just a few places, I'm going to give that a try.
For painted surfaces, you'll probably just have to start painting!