First of all, I never knew that squalor meant filth, I always thought it meant poverty, so thank you for that. When I was growing up none of my parents were particularly good at cleaning, and none prioritized it very much, and so when I got my first place after college, I wasn’t very good at it either. I had to learn to prioritize it and learn to make time to do daily basic cleaning, and deeper cleaning every few months. Like many “adulting” behaviors (paying bills on time, preventative healthcare, etc), living in a relatively clean home is not something that just happens naturally; it takes habit and conscious prioritization.