Uh yup that's what they're for lol I know a guy who built a GMC Sierra and I love his LED headlights, yeah everybody who has to see my headlights at night will hate me but I mean.... 😂
I don't know the expected lifetime. How good you are at putting it on has a huge factor I think, the more wrinkles on the outside edge the easier for dirt and dust to gradually get behind it until eventually it would just look awful. Personally I prefer the look over a smoked cover though. The cost... $10 or less I think? don't really remember. BUT keep in mind, it is only for people who have a lot more time and patience then money, because I cannot stress enough how painstaking, difficult, and downright frustrating it is to put on, even with an extra set of hands to keep the heat on it. Look it up on youtube and know what you're getting into before you buy, but my advice to anyone who is going to do it: HEAT and STRETCH. It's the only thing that works to get as many wrinkles out as possible, but don't expect it to be perfect. You will have a couple small defects and some little creases or wrinkles at the edge.
Thank you! Dying to get the brakes back together and go for a spin in this, it's been waaaay too long!