Sorry for the late reply, I didn't see your response earlier. I have been doing this practice for over three years, did the same for my previous cars(2002 Dodge Neon). It really doesn't streak off like you said, at the very least it doesn't for me. However, three months is the exact mark when I usually apply a new coating of wax. While there is no real need for protection, the beading up of water, and easy clean up of simple dust and any other continents makes my life so much easier. It also doesn't require me to always worry about my windshield being cleaned up. I live in an area that is labeled as a "rain city", so it works well for me. Again, it depends on the driver, for me it is just a very miniscule step since I already wax my paint every three months.