For a deposition or court appearance, the expert witness should always appear neat and professional. Business dress and professional demeanor are important. If the expert is in law enforcement or the military, it may be appropriate to testify in uniform. Otherwise, a clean, freshly pressed conservative business suit is recommended.

Flashy jewelry or other accessories are inappropriate for testimony appearances. These personal style items are not recommended, as these may detract from the aura of professionalism and credibility that the expert seeks to project. Fingernails should be trimmed and groomed, especially if the witness plans to use demonstrative aids to assist the jury or judge during testimony. Wedding and engagement rings and wristwatches that are not flashy are fine.