In more detail
The long version.
What the research actually found, why homes feel fuller than they used to, and the honest case against storing things.
What the research actually says
Attention, first
Neuroscience research at Princeton found that visual clutter competes for the brain’s attention: a crowded field of view keeps pulling at you, which makes concentrating harder and processing information slower. It is not a moral failing that a messy room is distracting. It is how vision works.
And stress
Researchers at UCLA’s Center on Everyday Lives of Families found that people who described their homes using words like “cluttered” and “unfinished” showed daily cortisol patterns associated with chronic stress, and a mood that declined through the day. People who described their homes in terms of rest and order showed the opposite.
Worth saying plainly: these are associations from a small number of studies, mostly in the United States. They are suggestive, not proof that tidying up will change how you feel.
Why it feels harder than it used to
The house shrank
Average one and two-bedroom apartments in South African cities have come down from around 67 m² to 55, 49 and in places 39 or 35 m². Bachelor units are quoted as small as 22 to 27 m², and micro-apartments of 18 to 40 m² are now a recognised category in Cape Town, Johannesburg and Durban.
The same possessions in two thirds of the floor area is not a discipline problem. It is arithmetic, and it is why the garage and the spare room quietly became storage.
You have not become messier. The rooms got smaller.
The honest case against storing things
Storage can be procrastination with a monthly fee
If you put something in storage purely to avoid deciding about it, you have not decluttered. You have moved the decision and attached a rental to it. That is worth saying on a storage company’s website.
When it is genuinely the right answer
It earns its keep for things that are seasonal, things that are genuinely valuable, things you will want in a different house, and things you are not ready to decide about yet but will be. The test is whether you can name the date or the circumstance when it comes back out. If you can, store it. If you cannot, it probably belongs in one of the other three piles.