For your allergic rhinitis, what you are experiencing is quite common because this condition tends to be long-term and symptom-based rather than completely curable. Montair LC (or similar combinations like Teczine M) contains an antihistamine and Montelukast, which help control the allergic response, so it is normal that symptoms improve while taking it and return after stopping, especially if exposure to dust, pollen, pollution, or seasonal triggers continues. Restarting a similar combination is generally used in practice for flare-ups, but ideally, it should be done under your ENT or physician's advice so the duration and plan are adjusted properly. These medicines are often used for a few weeks to a couple of months during active symptoms, and in some cases longer if allergies are frequent. However, long-term control is usually better achieved by adding a nasal steroid spray and avoiding triggers rather than relying only on tablets. If symptoms keep coming back repeatedly, a structured long-term allergy management plan is usually needed instead of repeated self-restarting of tablets.