They come in all sizes, from the flying foxes with a wingspan of about 6 feet to the bumblebee bat with a wingspan of about 6 inches. Bats have a life span of from 4 to 30 years depending on the species. While it is true that bats are wild animals and some of them do have rabies, the numbers probably are about the same as for any other wild animal. Some sources say only about one half of one percent of bats have rabies, and that these bats often die quickly and are not overly aggressive. America's bats are an invaluable natural resource.
Most bats eat insects.
I don't know about where you live, but aound my neighborhood there are two ponds, a river and a lot of wetlands. Now it's true that mosquitoes lay their eggs in standing water, and that doesn't apply to streams and most ponds. But the areas around streams and ponds can contain an awful lot of standing pools and puddles. That must be where we live. Ann can walk to the back of the yard and back and have a dozen or more bites.