Those with oily hair may need to shampoo more frequently, while those with dry hair may only need to shampoo once or twice a week.
Long hair tends to collect more dirt and oil, hence the need to wash it more frequently than shorter hair.
If you have a dry or irritated scalp, you may need to shampoo less often.
If you live in humid climatic conditions, your hair may become oily quickly and need to be washed more frequently.
If you have a physically active lifestyle, you may need to shampoo your hair more frequently due to sweat and dirt buildup.
If you have dyed or chemically treated hair, you should be more mindful of how often you shampoo it.
When using hair products, such as hair spray, mousse, or gel, you may need to shampoo your hair more often to remove the buildup of these products.
If you have a condition such as dandruff, psoriasis, or eczema, you may need to shampoo more frequently to keep your scalp healthy and flake-free.