One of the most important things in your life is your personal hygiene. Washing you bath towel might sound ridiculous, but it’s of a high importance. You might think that your towel stays clean on towel ring for a long time because you only using it after cleaning yourself. But, the very second that you use the towel it will become a breeding place for bacteria; dead skin; different types of secretions.
Most of these particles will not harm you. They come from your body, and they are always there, but they are multiplying very fast. There is a point when your flora will get out of hand and you will have to wash your towels.

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Three or four, say consumer and environmental health agencies. Any longer and towels can breed bacteria and mold.
Hang your towels properly: Spread them out on the rack (not bunched up) so they dry thoroughly. Before taking a shower, open the door and, if you have one, turn on the bathroom fan while bathing, so the air is less humid.
Keri Peterson // M.D., internal medicine, Lenox Hill Hospital, NY City
Some microbiologists and pathologists suggest that you can use it no more than 3 times, but only if you can dry them completely after you have used them. Furthermore, you can dry them completely only if you put them someplace dry so that they can air out in total.
If you towel has a funny smell, that means that it has microbes growing and it is high time that it is washed.
Oxygen, water, warm temperature and neutral PH are everything that makes a perfect breeding ground for the germs.
Most of the germs in our household are not dangerous but you can never be cautious enough. You can’t be sure that those, growing your towel are not harmful as well.
Please, be sure not to share your towel with other people. If you do so, your skin can come in to contact with small organisms that your body is not used to. That can be damaging to your skin, or even worse. Sometimes, it won’t be serious you can get just a pimple. On the other side, it can lead to infection.
However clean your towel may seem, it is dirty and disgusting and you should probably be washing it much more than you are.
Conclusion
In the light of everything that we previously said, you should wash your bath towel pretty frequent. In other words, washing it after 3 baths might be just enough, but anyway, you need to dry it every single time you use it in some dry room.
As we mentioned, this might cause some problems but not necessarily damaging ones. Therefore, prevent even those small ones in a form of a pimple with washing your towel more frequent.