Laundry is one of the least enjoyable activities. Wanting to know how many times you can go without washing your bath towel is completely understandable. However, just like "How much rope is there, exactly?" The answer to this question will depend on whom you ask. Unless, of course, you ask a microbiologist. But let's first clarify one issue...
Yes, it's definitely dirty!
Some people think that because you only use your towel to dry your freshly washed body after a shower or bath, it doesn't get dirty. But they are wrong. Your body is a wonderland. But one that is literally teeming with billions of invisible microorganisms like bacteria and fungi! In fact, they are so tiny and numerous that showering or bathing will never get rid of them 100%. However, they will enjoy a free ride on your towel as you dry off. Initially, this is not a problem. Bacteria and fungi are everywhere. But if your wet towel stays that way and doesn't dry out completely as quickly, it becomes the perfect environment for this microbiota to grow.
Time is of the essence
It's crucial to ensure that your towel thoroughly dries in between usage to prevent unintentionally transforming it into a gathering place for germs, mildew, and fungus. However, it is even better to ensure a FAST drying. A study by a team of microbiologists showed that drying bath towels on heated towel rails reduced their microbial load from 1,000 mmol/g to just 1 mmol/g! Towel dryers work fast! In fact, a high-quality heated towel rail can dry your towel completely in just four hours! Thus, you can increase the breeding time of bacteria and fungi.
So, Big Question!
Understandably, when it comes to judging how “dirty” your towel is, you should use your head, not your eyes. If it's been damp longer than dry in the last two days, you'll want to wash it. However, if it's dried quickly after every use, it will definitely have a lot less "nasty stuff", meaning you won't have to wash it as often to keep it clean and hygienic. A lot of people don't realize it, but it's the main reason why heated towel rails are so popular in the bathroom. They don't exist to warm up your towels - their job is to dry them and do it quickly. This way you can wash less; you don't have to rely on sunny weather to dry, and you don't have to turn on a power-hungry tumble dryer.