What must be done before performing a perm?

Conducting a strand test is a critical step before performing a perm. This test helps to determine how the hair will react to the perming solution, allowing the stylist to customize the treatment according to the individual hair type and condition. It provides valuable insight into the hair's porosity, strength, and elasticity, which are essential factors in achieving the desired curl pattern and ensuring the hair's health throughout the perming process.

By assessing a small section of hair, the stylist can see how long the hair needs to process with the perm solution and whether any adjustments need to be made for optimal results. This precaution is fundamental because it helps prevent damage and ensures that the perm will take as intended without compromising the integrity of the hair.

In contrast, the other options, while potentially important in different contexts, do not directly address the necessary preparatory steps involved in safely and effectively performing a perm. Styling the hair first, applying a deep conditioner, or merely consulting with the client does not substitute for the critical insight gained from a strand test.