People with allergies often take their medications only when they have symptoms that bother them. But to get the most out of your allergy medication, it's best to take it regularly, even when you are not experiencing symptoms. This ensures that you get optimal relief from your medication.
For example, if you're using a medication for seasonal allergies, they are most effective if you start them before you experience symptoms. So it's important to know when your symptoms start each year and to take your medication regularly, as prescribed by your doctor and until the end of the allergy season.