There are two phases:
Buildup phase: You get shots frequently (up to twice a week) for 3-6 months to help your body adjust. You’ll need to stay at the doctor’s office for 30 minutes after each shot for monitoring.
Maintenance phase: Once your body is used to the allergens, shots become less frequent (once or twice a month) and can last three to five years. It’s important to avoid missing shots during this phase. You’ll still need to be monitored for 30 minutes after each shot.