Question about the Brown Pyramid of death

Since we travel a lot in the Winter in freezing temps, I never even hook up our sewer hose until it is time to empty our tanks. For the wife and I, we can usually go 5 days or so before we need to empty our holding tanks and fill our fresh water tank. This has the advantage of keeping fluid in the holding tanks long enough to soften all solids so that the tanks drain completely. It also means that for this somewhat unpleasant task, I only have to do it every five days or so.