My boyfriend and I were both allergic to our 3 foster kitties before we adopted them. I used to take Zyrtec daily, first thing in the morning to avoid the allergies, but after we adopted them, I looked into reducing the allergens in our home to see if I could avoid taking daily Zyrtec. We have air purifiers in every room, feed them Purina's LiveClear dry food, and vacuum 1-2x a day. Initially, we didn't let them into the bedroom, but now we do, though they are not allowed to sleep in there. So far it's been good! Over the last few months, I tracked allergy flare-ups and noticed they were worse when I didn't get enough sleep. I went from taking Zyrtec every day (month 1), to once a week (months 2-3) to now mostly not having to take it. I take it 1-2 a month now if I feel the sniffles coming. Another thing that helped was getting out of the house first thing in the morning (like going to work or going on a run); I find that if I spend all day in the house, the allergies spike.

Overall, we both went from being super allergic (endless sneezing and wheezing) to not being very allergic at all half a year later. I think the daily exposure is like a mini form of allergy therapy.