[britzkopf]

I've bad hay fever, for which an allergist prescribed corticosteroid nasal spray. When I told him I didn't want to take it until allergy season because of dependence, he told me that's not a problem and the drug will work better if I take it ALL the time. He is the medical professional I guess but I still couldn't bring myself to take that advice.

[ch4s3]

People build weird behavioral dependencies around nasal sprays in rare circumstances, but its not a real risk. If you take enough corticosteroids long enough you can have mild withdrawals after stopping but again its not really a thing to worry about.

Your doctor is right, corticosteroid nasal sprays need to be taken before the onset of symptoms to be most effective. They basally dampen the allergic response and if you already have a bunch of immune signaling molecules bouncing around its too late.