It is recommended that a person waits four to six weeks between dye jobs to minimize the risk of damaging the hair shaft, as the hair could break or get a rough, undesirable texture and appearance. Waiting longer, however, will allow the natural color to begin showing at the roots.
There are exceptions to this general rule. Sometimes the desired color can't be achieved in one session. It is also possible that the stylist failed to understand what the customer wanted. If either is the case, it is best to contact the stylist, as they are trained to assess and treat hair to ensure minimal damage.