Their absence would create problems unimagined. We all wish there was a bee and wasp repellant, but unfortunately there is not and we have to deal with these pests one nest at a time. Sometimes the problem is finding the nest. Wasps make paper-like nests that can be visible, made in a tree or even on your windowsill. Many people find them in the attic.
Carpenter bees leave sawdust as they drill into wood to make their nests.
The holes look man made, smooth little circles. Other nests can be more difficult to locate. These insects can adapt well to many types of environments, they nest in the ground, under shingles and siding, in eaves, in a log, a tree, a bush. A few minutes spent watching their activity can reveal where they've set up house. You may notice them hovering about in the same general location every day.