We have horrible Black Widows. The house was built two years ago and we have decided they feel they were here first and they aren't leaving
Before we moved into this house, I had serious spider phobias of anything with eight legs. Now, I can deal with anything. Orb Weavers are freaky looking, TX tarantualas are funny looking, wolf spiders can look like brown recluses if you don't know the difference but they are all actually good and help to keep the bad stuff at bay.
Okay, on a serious note - Black Widows are extremely difficult to kill through regular bug extermination. We treat the house and yard thoroughly every month which kills off most of the yucky stuff but we still have to hand treat for black widows outside. From what our exterminator has told us and what we've seen the last two years, black widows have a high tolerance for bug spray and they don't pick up enough on their legs when they walk through it to kill them. They have to be sprayed directly on their bodies to do any real damage. This means we do a nightly "round up" since they tend to come out more at night. We have spray cans of bug spray and go way overboard on each one. We then vacuum or sweep them up and throw them away. Do not smoosh them, it only spreads the venom on the ground and then bare paws and feet will pick it up until it washes away.