Final answer:
Periodic strand testing is crucial during the hair relaxing process to monitor the change and prevent over-processing. This step helps in determining when the hair has been sufficiently relaxed by checking its texture and elasticity.
Step-by-step explanation:
Periodic strand testing during processing will help inform you when the hair is sufficiently relaxed. This is an important step in both perming and relaxing treatments, where chemicals are applied to the hair to alter its structure. In the case of chemical relaxing, the goal is to flatten the hair's natural curls or waves, and strand testing ensures that the hair is not over-processed, which could lead to damage. By taking a small section of hair and checking its elasticity and texture at intervals during the chemical treatment, you can better gauge when the hair has reached the desired level of relaxation.