I travel a lot and I will come in to brief 100,000 km Fahrleistung- while I drive all freeway, highway and city. Because me poor visibility in wet conditions have always been disturbed, I have already tried many Regenabweiser, all somehow works, just not as good and long as Rain-X. It is fair to say, the more you apply the remedy, the better it holds on the disc, after 3-4 applications however, it is then "fed" to the extent that the effect is still a few months later, at least on the highway at speeds above 100 km / h noticed. The slower you go, the more "fresh" should be the seal, to say: Who wants to do without in city traffic on the windshield wipers, which should already be applied once a month.
Keyword wipers: the real enemy of Versiegelung- if you can do without it, then you should do what is absolutely, you look at the good stuff then rubs only from the disc. Big advantage: also recommended for very dry summer, the flies go with it easily from the windscreen!