Last year it rained here constantly (well it seemed like it) all spring, summer and autumn. I never had to water the garden not even once last year. Plus it is hot and humid here in summer.
You have to spray on the east coast with a systemic fungicide or you will get blackspot. Since I hate the looks of blackspotted leaves, or even worse, bare sticks with no leaves, I spray. Always!
I sprayed today again as I am already on my summer spraying schedule. Last year I started much later than this. However, this had been such a warm March that things are way ahead of schedule. For instance, the Azealeas never bloom before the beginning of May and they are just starting to bloom now already. Way early.