Final answer:
In the cosmetology industry, it is important to always have multiple combs available to maintain hygiene and to use the best comb for various hair tasks.
Step-by-step explanation:
A good rule of thumb for a professional in the hairstyling or cosmetology industry is to have multiple combs available at all times. This ensures that you can maintain hygiene by using a clean comb for each client, and also allows you to use the most appropriate comb for the specific task at hand, such as detangling, styling, or cutting hair. Having a variety of combs at your disposal is essential for providing professional and efficient service to clients.