The advantage of acidulated phosphate fluoride solution is-

Advantages of acidulated  phosphate fluoride  Requires only 2 applications in a year and is thus suited for most dental office routines.  The gel preparation can be self applied and thus the cost of application also gets reduced.  It has the ability to deposit fluoride in enamel to a deeper depth than neutral sodium fluoride or stannous fluoride  APF is stable and need not be freshly prepared for each patient.  Disadvantages of acidulated phosphate fluoride  Practical difficulties like the teeth should be kept wet for 4 minutes. So repeated applications  necessitates  the  use  of suction thereby minimizing its use in the field. This also increases the chair side time making this method more expensive.  It is acidic, sour and bitter in taste.  It cannot be stored in glass containers.  Repeated  or  prolonged  exposure  of porcelain or composite restorations to APF can result in the loss of materials, surface  roughening  and  possible cosmetic changes.