I have used 8 syringes in a session several times... I generally would not do this on someone who has never had fillers before. I would prefer to bring them back monthly as doing that many can be a little frightening for a new patient... If you are in your 60s and have not had fillers you might need as many as 10 or 15 syringes for full correction .
A good estimate is a kit of 5 syringes for every decade over the age of 40 if you are building mid facial volume. If you are focusing on one area such as under the eyes, the quantity will be much less. Because Bellafill has a duration of 5 years, it is best to be conservative. I typically do not do full correction on my patients at the first visit due to Bellafills longevity. A follow up in 4 weeks is made for continued treatment.