I've tried wax from several places, just ordered some Plex-master and haven't used it yet. Russ' Super Spray Wax is the best of everything I have tried. We use it as a separate step after washing and rinsing. I hate getting it on the windows as it makes them hydrophobic and hard to clean with a water fed pole. I did some side by side testing on my own home and mildew returned to the section without wax in about 12 months, and and mildew returned to the section with wax in about 18 months. This was on the north side in the shade. It doesn't change the appearance of the siding when it is dry, in my opinion.