We too have been many times (11 and counting

) without bugs being an issue, until last Sept. For the first time we were bitten by bugs. Some tiny little gnat things. Not the love bugs we saw so many of, but the gnats. We were first biten when we went off property (I know-it's my DM, she can't stay at Disney the whole time

) and we were really eaten up

(and they don't usually bother me at all!) at the Merrit Island Refuge and then a short time later while watching manatees off some, close-by,river. The next day when we went to AK, we felt a few more bites, so we purchse dsome OFF spray, at one of the stores. Better to bring your own (towelettes are a great idea) since it's more expensive in the parks, and not all the stores carry it.
FYI, we found out last trip that besides being able to get the regular items like aspirin, bandages, antacids, etc. at first aid locations, you can also get this gel type ,anti-itch ointment, that works great.

You can also get those small, one-time use, contacts lense solution vials.