Things like to grow on wet stuff. Even if you're clean, wet towels will start to grow things and get an odor. The quicker the towel gets dry the quicker it doesn't grow stuff.
IMO it matters more how long it has been since you last washed it, not how wet it was. It also depends a lot more on the climate. A wet and humid client will be worse than a house with central heating in the winter, where things are notoriously dry.
Why does your towel need to be washed more often if it gets wetter?
The water coming off your body is pretty clean (you just showered).
Things like to grow on wet stuff. Even if you're clean, wet towels will start to grow things and get an odor. The quicker the towel gets dry the quicker it doesn't grow stuff.
IMO it matters more how long it has been since you last washed it, not how wet it was. It also depends a lot more on the climate. A wet and humid client will be worse than a house with central heating in the winter, where things are notoriously dry.