Determine your hair type
As with any shampoo or haircare purchase, first, you must determine what your hair actually needs. Is it dry and in need of moisture? Is it curly and in need of some definition? Do you need something to help eliminate product buildup? Once you determine your hair type and concerns, you can pick a bar formulated for those needs.
Consider your hair wash routine
How often you wash your hair will determine how long your shampoo bar lasts. Just remember, no two people will get the same number of washes out of the same shampoo bar, so you might want to determine the size of the bar to compare it to the liquid shampoo you’re currently using.
Another thing to consider is your dexterity. Shampoo bars have a learning curve because you have to hold your hands differently as opposed to using liquid shampoo. Think about what shape bar you might feel most comfortable using.
Do you wear a protective hairstyle?
People with protective hairstyles might find it more difficult to use shampoo bars because it’s harder to lather and thus harder to get to the scalp, notes Dixon. Liquid shampoo, on the other hand, “can be applied directly to the scalp from the bottle with little saturation of the strands.”