The NXT lasted 6 months for me. I waxed in Feb, and I just waxed again this weekend. Normally I don't wait more than 3, but I wanted to see what it'll do. The water would still bead off the car, but it was not as tight, and starting to get a little harder to clean. I'm very impressed, as I work at the space center and have to park outside all day. Granted I am OCD when I wax and do clay, cleaner, polish, and then 2 coats of wax (one 24 hours after the other). I don't know if it'd hold up as well on the black, but it's the best thing I've tried yet vs. Mother's, Zymol, Zaino, Meguiar's Gold Class.