Sometimes its not even your own home. Used to live next what I referred to as the "hillbilly house". Backyard was full of old piles of wood and random junk. Weeds grew everywhere. No yard maintenance was being done. Because of them I would find 2 or 3 black widow spiders in my yard every week. I bought a big tub of pesticide and would spray around the base of the block wall separating us, and that helped, but some would still make it through. So I would just spray wherever I thought would be a good spider hangout, and then just made sure to be careful when I was outside at night. Biggest problem was the pool filter. It was in a corner of the yard, and there were plenty of holes and shade for the spiders. Problem was that I had to go over to do pool maintenance(backwash, clean the filter, let the air out, set the timer, etc...). I used to carry around a shortened broom handle as my "spider stick".
Once the hillbillies moved out, the problem went away.