6. They dilute and swap bottles.
There are many salons out there who have been refilling expensive lotion bottles with cheap, generic ones. All along you were thinking that you were getting a high end product on your manicures but you are just being deceived to believe so. The same way goes for old nail polishes that have become clumpy because of old age. Salons dilute them thus, compromising their quality. Don’t just bring your own instruments. Bring nail polish, too.