I run across brown recluse and black widows on a daily basis, as well as wasps, hornets, yellow jackets, and the occasional snake too.
I buy really good wasp and hornet spray by the case, and carry a couple cans on the truck...stuff works well on spiders too. I keep the .357 in the truck loaded with rat shot for the snakes. You never know what your gonna find when you open up an air conditioning unit.