A RoadTripping pet peeve of mine is bugs on the windshield in the warm weather months as well as dirty/salty spray in winter. I always keep a gallon of fluid in whatever family auto or rental I'm driving.
Given the high level of grasshopper hits I'd had back in my '02 RoadTrip to Montana and back (when they were so thick I had to pull off and power-spray them out of the radiator twice in one day due to overheating!), this year I bought a new long-handled squeegee and a fresh bottle of Windex for the in-between fuel stop touch-ups. After the squeegee purchase, I stumbled upon a product I decided to try.
It's Rain-X Bug Removing windshield fluid, and it worked great. I bought a gallon of the CONCENTRATE at Wal-Mart and proceeded to mix it at roughly 1.5x the recommended levels with standard "blue" fluid. My wiper refills were brand-new for the trip, and between the good blades and the Rain-X, I never touched my squeegee and even made some fuel stops without using the truckstop tools. The Rain-X worked particularly quickly and well when applied shortly after a big hit. It would also remove dried/sunbaked bug crud. I did go through the entire gallon during the 5,779 mile RoadTrip, but at something like $3.50 for the gallon of concentrate, it was a cheap, simple way to keep the view from the driver's seat clear and safe.
I'm sure to purchase another jug next trip I make to Wal-Mart.