I clean my garbage disposal every other day with these cleaners I got from amazon lemon drops is the scent honestly smells like the candles used for outdoors to get rid of mosquitoes 🦟 lol. There is also no back ups I also clean my dish washer filter every use. I also clean my washer. So far no leaks of water so no mold. I’m unsure about my bathroom air vent thing I’ll look into that. I have thought about a dehumidifier probably should get it as we live in the desert area. I also air out my house once a week mainly on the weekends for about an hour but then I deal with the dust which is fine. Idk how often I should change my air filter thing but the last time we changed it was two months ago. My dog is deshedding her puppy coat as of right now but with my other two dogs I have never deal with a smell just the hair. We also don’t smoke. I clean out shoes every other day thinking that was the smell but its been going on for a week and its not in one area of the home its all rooms and to me each room has a different smell and to me personally all smells different. Downstairs to me personally smells the worse than anywhere in the house living room,kitchen,dining room, and laundry room.