The cleared threshold
The entry sets the arrival. Tradition treats it as where energy enters the home; the clutter research treats it as where the stress response starts. Both agree it should be clear.
What the tradition says
The front door is the mouth of qi, the point everything enters through. A blocked or dark entry is treated as the first thing to fix in a house, before anything further in.
The part that measures
Clutter is associated with flatter cortisol slopes, more procrastination and lower subjective wellbeing across several small studies. The effect sizes are modest and the samples are not large, so read it as a real direction rather than a large lever.
Light and the door itself
A working light and a door that opens fully do more than any object you could add. A door that only opens partway, because of what is behind it, is the single most common entry problem and the easiest to fix.
The thirty-second habit
Everything that came in with you either goes to its place or onto one designated tray. The tray gets emptied when it is full, not daily. Systems that demand daily perfection are the ones that fail.