Anecdotally, I noticed that I am much happier and more focused after I clean and declutter my apartment. Clean, flat surfaces, nothing for your brain to process.
Even if it's your own apartment or a house, your brain will constantly have a "thread" firing on all cylinders that tries to parse what you are seeing, non-stop.
If it's things all around you, small details, objects - it will sap your mental energy and you won't even know why.