They show up here in the spring. Some people will have a whole bunch in their home all of a sudden, yet the next door neighbor may not have a one.
We usually see wasps in the house in the spring. They nest(?) in the attics, then when they wake up, they come into the living space through the heat vents...
The worst though are fly infestations. In the 20 some years that I have lived here....I've only had them a couple of times. Big suckers and they are just suddenly in the house...and are gone a day or two later, as quickly as they appear.
M sprays around the foundation of the house, and the bushes and flower beds several times a year....I hate bugs...but I reallllllllly reallllllllly hate spiders.... 
You know, I always kind of sort of wondered about something.
Does one suppose cats are good insect-repellants?
I used to notice, while living in Lincoln, that friends who had cats in their apartments, even if McKinley-era buildings, never had cockroaches, while friends who didn't have cats, even in
moderne nouveau habitations, had cockroaches.
(The city of Lincoln sits in a "basin," which might account for this.)
When I moved out to this property, which hadn't been lived in for 10+ years, in the autumn of 2005, there were spiders, flies, wasps, and other insects, footed and flying, all over the place, and snakes and rabbits bouncing all around outdoors.
It's now been about four years since I last saw any of the latter species, and the indoor insects, while around, are virtually nil.
One wonders if Abbie, Snow, the late Junior, the late Apricot, the late Floyd, the late Gordon, Harold, the late George, Ellie, the late Leo, Gustav, William, and the now-gone-to-another-home Decker, have, or had, anything to do with that.
