What level in dressage do you use a double bridle?

A double bridle is typically used at the FEI levels of dressage, starting from the Intermediate Level and up, including Grand Prix. It allows for more refined communication between the rider and horse, as it uses two bits: a snaffle and a curb. Riders at lower levels usually compete with a single bridle, which is sufficient for their needs. The use of a double bridle is often seen as a sign of advanced training and skill.