This really depends on the choice of filler. Below is a basic rule of thumb guide to how long the different brands typically last. Your mileage may vary, as they say, depending on how quickly you metabolize the product:
Juvéderm (Ultra, Ultra Plus, Ultra XC, Ultra Plus XC) – 4 to 6 months
Restylane – 3 to 4 months
Voluma – 6 to 12 months
Volbella – 4 to 5 months
Perlane – 4 to 6 months
Radiesse – 8 to 18 months
Sculptra – 8 to 18 months