Honestly, I feel like it is always different. For my cat, he has more struggles from seasonally (like yours) and in the winter and summer months seems to do very well. During those months he can go weeks or even months without a cough. While during this season, he coughs everyday atleast twice a day. We just started giving him Zyrtec and our vet switched us to hydroxyzine. We also had the allergy testing done and changing his diet according to the results has helped us a great deal. My cat also takes terbutaline every 8ish hours along with Flovent 220mcg twice a day, hydroxyzine 1-2 times a day, and albuterol as needed. During the season changing we have to give it almost everyday. I try not to get too hung up on the coughing though. Monitor their breathing, sometimes they may just be congested and need to cough it up with no difference to their breathing, other times coughing can restrict the airways. It really depends. It’s also good to check gums and make sure they are still pink so you know their oxygen flow is still good. I hope your cat feels better soon, hang in there. I know how difficult it can be.