I don't use the stuff very often, and when I do very sparingly. Generally, I only put some on if I happen to have the bike on the jack and can turn the wheels freely. That's typically a once a year thing. So, once a year, I put some on my tires. Other than that, I don't lose any sleep over the issue of what the tires look like. My back rim, now that it's black, gets dirty fast. Whatever it is that dirties up the rim, also dirties up the tire, and just wipes off with a rag. Especially if it's not long after putting some of the shiny stuff on the tires.
The Metzeler 280 has such a small sidewall, it's almost not worth worrying about.