why are some doctors here on real self and some I had consults with in person recommending I come back for lip fillers every 3-6 months when others say they should last at least 9-12 months for Juvederm especially if you get 3ml in one year? Who is more accurate? I hear doctors now saying they last way longer than 3-6 months and to only come in once or twice a year after reaching the desired outcome.