In many salons or high end spas, the massage therapists are required to wear a uniform or scrubs. In small practices, it is the therapist's preference. If your therapist's attire makes a difference to you and your ability to relax and enjoy your massage, feel free to ask this question before you book an appointment. But remember, a uniform does not make a good massage therapist. Asking about their credentials might be a better question to ask. Look for your therapist's diploma from an accredited school on the wall and also a license to practice massage therapy in the state or city you are in. With a few states still not requiring licensing (Kansas), you should be weary of massage establishments that do not make credentials visible for clients to view.