"Pretty good" ain't good enough! I want mine to be as bright as possible. 'Ever run up on some idiot with blacked out tail lights in dense fog? It might not happen soon, but there's a rear-end collision waiting in the future.
The OP only blacked the backup lights. Have you ever followed someone with darkened taillights or brake lights through fog? They definitely increase your chances of being hit from behind! They are popular, but a really dumb idea!
I see a lot of not-very-old cars and trucks with rusted out fenders and bumpers. I'm a lot more worried about the nasty effects of road salt than I am almost unnoticeable swirl marks. Mine gets frequent washes that includes a good strong underbody wash as often as it needs it to continue to...
After a quick hose & soap wash, I dry them and then hit them with a quick wipe with Meguiars Quik Detailer and they look like new. They don't get slick like ArmorAll would make them.