I bought this on a whim while I was stepping up my windshield wiper game and it definitely helps make water bead and run off my car windows. In light rain you don't even need wipers. It's worn off over time and I haven't bothered reapplying because, while its nice, it's not exactly a necessity, and I'm kind of a lazy man. Let's face it, glass and water are both pretty good at being frictionless on their own. I have it in my bucket of car detailing supplies, right next to my back-to-black trim treater and my headlight de-fogging paste, awaiting motivation to strike.