What should be assessed before performing any chemical service?

Before performing any chemical service, it is crucial to assess the client's skin type and allergies. This assessment is essential because chemical services often involve the use of substances that can cause allergic reactions or irritation, particularly on sensitive skin. Knowing a client's allergies helps to avoid products that may trigger a negative response, ensuring their safety and comfort during the service.

Additionally, understanding the client's skin type allows the barber to select appropriate chemical products and techniques tailored to their specific needs, minimizing the risk of adverse reactions. This proactive approach prioritizes client health and satisfaction by ensuring that the services provided are suitable and safe for them, reflecting a professional standard of care in the barbering industry.

While other factors like hair length, preferred length, and haircut history are relevant in different contexts, they do not directly pertain to the immediate concerns around safety and potential allergies relating to chemical products. Thus, assessing skin type and allergies is the most critical step before any chemical service.