Thank you for the question. BBL is typically a procedure that transfers unwanted fat from the hips and other areas to the buttocks. There is some element of unpredictability as to how much of the transferred fat survives. Survival of the transferred fat depends on the quality of the fat, method of harvest and processing, method of fat transfer, injection technique, anatomy and blood supply of the recipient site, and how much fat was transferred. Any quantity of fat that survives after the initial postoperative period will become permanent. So, to answer your question, you don't have to repeat the treatment periodically, unless you are not satisfied with the results and would like to consider secondary fat grafting to enhance the projection. Please discuss your specific concerns with your surgeon. Also, ask your surgeon to show you before and after pictures of his/her patients. Best of luck! Pej Aflaki, M.D. Johns Hopkins-trained plastic surgeon