All part of the job, Dawg. I am an Extension Specialist (and a Master Gardener) and some days, I get 5 people in here with that exact question.
I am pretty much all organic, so I rarely turn to chemical controls. (WIth the exception of poison ivy. I would go nuclear on that stuff, if I thought it would help.) Mulching may solve all of your problems, and buying plants from different grower might help too. I grow my own, but if I was buying, I would go for a local, smaller grower than the folks who supply WalMart and Lowes. If you pick the blighted leaves off, don't compost them--burn them or send them to the landfill. And wash your hands/tools before you touch healthy plants.
I just haven't been the same
since that house fell on my sister.