The best feature (undocumented) about rain-x is, that it makes bug splatter come off easier too. We do a lot a driving on FM roads in TX at night on our trips from DFW to the Grandparents around Houston (leaving after work on Fridays). I have found that doing the windshield just before we leave makes all the bug splatter come off with just the windshield fluid and wipers. I've tried most the brands of wiper fluid out there, and nothing has worked as well as just applying rain-x before the trip.