*indiej: actually Klasse SG should outlast Collinite. Klasse SG to put it down to the basics is like applying a very very thin layer of polyer film on your car. Now this film helps in preventing oxidation as well as color aging as its main function, and preventing watermarks just come as a bonus. Now if you apply 1 layer of Klasse SG this should actually be enough to cover your car for 3 months harsh weather but layering multiple layers of klasse SG also thickens the layer of polymer film, now whether you apply 1 or 3 or 5 layers of Klasse SG it will all boil down to how deep the water mark can eat through the polymer film and eventually the paint. Lets say you apply 1 layer of SG and you get lucky that the water left on your car was cleaner and dried quickly lets say it was a windy day then your SG should still be able to hold up. Now if its acid rain or the water you used has a high mineral content then even if you slap on 5 layers on klasse SG it would still eventually eat through. The proper mind set on klasse SG would be that its just a tougher sacrificial layer on your paint. Tougher in the sense that sealants have a denser chemical composition. Collinite can also provide protection but it would last a lot less than the klasse SG since its a wax, and waxes no matter how they claim to resist soap is still wax and soap in its nature will still fade out wax.

As for the claims of collinite lasting for a very long period of time, that is actually true and there's no exageration there, but you have to take note that collinite waxes lasts that long in their country's condition. In our country sadly, the weather takes a huge toll on our paint, if collinite can last up to 6 months for them for me its at most only up to 2 months and 2 weeks tops. Other claim that Mom's Step 3 can last up to 3 months in US, heck i'd be happy if it could last me 2 weeks of rainy weather here in the philippines.

The best way to maintain a nice paint job and in your situation, prevent water marks would be to have a layer of wax everytime it rains, in short wax regularly. If a monthly waxing regimen can't hold or deliver the protection you need then you might consider waxing every 2 weeks.

Now if you already have klasse SG and want that really tough protection, then try what time doing at my daily drives. 2 layers of Klasse SG and 2 layers of collinite 476 every 6 months for starters, just also be sure that you have removed that water marks, followed by a weekly spray wax treatment after my weekly car wash and maintained by 845 for its monthly waxing. So far it has given me great results, im saying this because what might be sufficient for my cars paint condition might not be sufficient for yours. But of the myriad of products i've tried this has by far given me the best protection and not to say less important, proper washing is also equally important in maintaing a wax's durability, so always use wax friendly shampoos