I run my robot vacuum cleaner each day to pick up sand and dust that gets brought into the house from unknown sources.
Well, actually the sources are pretty known because it is only I who is coming and going each day from the flat.
My cats both live indoors full time so they aren’t bringing in any dirt. I have a HEPA filter on the robot and it picks up all of the sand and dust that my central HVAC system would normally be grabbing, so I end up not needing to clean the filter in the main unit that often. I looked at the filter the other day, after three months of not checking it, and it was still perfectly clean. I think I could fill up a small waste can in a month with all of the stuff that the robot picks up from the floors. It’s really amazing how much dirt gets into a house that is closed up with a climate control system running each day to keep the air clean. I bet in a year you could fill up a bathtub with all of the things that accumulate in the house over that period. Imagine breathing in all of that stuff if you didn’t have an HVAC system or HEPA filtered robot to keep the house clean. I need to ask Google how all of that debris gets into a house that is totally closed up. Maybe it comes in on my clothes and my body, not to mention my bike. Be kind to yourself today.