Belts are great if you are wearing jeans or suits but, this is a big no if you are wearing a tuxedo. Never wear any belt with formal wear, not even a suspender even if it does look classy. Tuxedos should have a strong waistband so you don’t have to wear belts. Wearing belts is not a good addition to your tux so you must find an experienced tailor for this. Taking proper measurements ensures that you don’t need belts or suspenders underneath. Unless of course, you don’t like wearing pants without belts!