Low porosity hair tends to accumulate less dirt and oil than other hair types, so it typically doesn't need to be washed as frequently. In fact, over-washing low porosity hair can actually strip it of its natural oils and make it more prone to dryness.
As a general rule, low porosity hair should be washed no more than once a week or every two weeks. However, this can vary depending on your individual hair needs and lifestyle. If you are very active and sweat a lot, you may need to wash your hair more frequently. On the other hand, if you have a more sedentary lifestyle and your hair doesn't get dirty or oily easily, you may be able to go longer between washes.
It's important to pay attention to your hair's texture and appearance to determine when it needs to be washed. If your hair feels dry or brittle, or if you notice a buildup of product or oil on your scalp, it may be time to wash your hair. On the other hand, if your hair looks and feels healthy, you can probably wait a little longer between washes.