The pre-service inspection: what a good beautician checks before opening the kit
For hair work generally, the checks are quick but specific: a porosity check, wetting a strand to see how fast it absorbs, which decides processing time; a look at the scalp for irritation, psoriasis or folliculitis, which are reasons to pause and, for anything persistent or painful, reasons to see a DHA- or DoH-licensed dermatologist rather than a beautician; and a history question about henna. Henna matters because conventional dye and lightener over henna-treated hair can react unpredictably, and a lot of hair in this market has henna in its history even when the client has forgotten.
For nails, the equivalent inspection is of the nail plate and surrounding skin. Greenish discolouration under old gel, thickened or crumbling nails, or broken skin around the cuticle are all stop signs, some of them fungal or bacterial, and working over them seals the problem in. A conscientious technician will decline to apply product over a suspect nail and suggest a pharmacy or clinic visit first. That refusal is not upselling caution; it is the professional protecting you and her licence.