I have textured vinyl siding and it's not so hard to maintain like the other ones. As much as I know it's good to clean it every year, but I did it maybe once in three years or so. Before I had some usual exterior paint and I didn't really bother to clean that, but once I upgraded to the vinyl siding I tend to take more care of it. Thanks for sharing the link though, I'm not so informed about this theme yet. The guys who cleaned my house siding before didn't do such a great job, so it's great to have other options on hand.