I hate to break it to you, but your bath towel is dirty – really dirty. The moment you use it, it becomes a breeding ground of bacteria; fungi; dead skin cells; salivary, anal and urinary secretions; and many other germs lingering in your bathroom that may have hopped onto your towel – including droplets from your toilet.
While most of these microbes aren’t likely to harm you, given that most of them probably came from your own body, they’re there, and they’re multiplying quickly.
So how many times can you use your towel before before concentrations of your own flora get so out of hand that you need to wash it? “If you can dry it completely, no more than three times max,” Philip Tierno, a microbiologist and pathologist at the New York University School of Medicine.