When should a client be advised against certain hair treatments?

A client should be advised against certain hair treatments if they have undergone recent chemical services. This is due to the potential for chemical interaction between new treatments and residual chemicals from previous services, which can lead to adverse effects such as hair damage, breakage, or undesirable results.

For instance, if a client has had a perm or a relaxer recently, applying color or another chemical treatment too soon can alter the effectiveness of the service and negatively impact the hair's integrity. Understanding this timing is crucial for maintaining hair health and achieving the desired results.

In contrast, while dry scalp might necessitate caution, it is not an immediate reason to avoid hair treatments altogether. A haircut typically does not affect a client's eligibility for other treatments; it's a standard service that can be performed without restrictions. Advising someone before a color treatment is standard practice, but it doesn't specifically address any contraindications that arise from previous chemical services, making it less critical than the correct choice.