You've already made hundreds of decisions today. What to eat. What to wear. Which route to take. Whether to open that email now or later. Whether to keep reading this sentence.
By some estimates, an adult makes around 35,000 decisions per day. Researchers at Cornell University found we make 226 decisions about food alone — what to eat, when to eat, how much, whether to finish the plate.
Most of these are unconscious. You don't feel yourself making them. But your brain does.
Decision fatigue is what happens next.
Psychologist Roy Baumeister demonstrated that willpower and decision-making draw from the same limited pool of mental energy. Each decision — no matter how small — drains the tank slightly. By evening, the tank is running low. You make worse choices. You default to the easiest option. You skip the gym. You order takeaway instead of cooking.
The scariest proof comes from the courtroom.
A landmark 2011 study published in PNAS tracked 1,112 parole decisions by Israeli judges. At the start of each session, 65% of rulings were favourable. By the end of a session — just before a meal break — favourable rulings dropped to nearly zero. After the break, they snapped back to 65%.
The judges weren't biased. They were tired. Their brains defaulted to the safest, easiest decision: deny.
This is why some of the most successful people on Earth wear the same outfit every day.
- Steve Jobs owned 100 identical black turtlenecks. He wore the same jeans and New Balance trainers daily. One fewer decision every morning.
- Mark Zuckerberg wears the same grey t-shirt. He said he wants to "make as few decisions as possible about anything except how to best serve this community."
- Barack Obama only wore blue or grey suits as president. He explained: "I don't want to make decisions about what I'm eating or wearing, because I have too many other decisions to make."
- Albert Einstein bought several identical grey suits to avoid thinking about clothes.
This isn't a quirk. It's a strategy. By eliminating trivial choices, they preserve cognitive energy for the decisions that actually matter.
The concept has a name: the capsule wardrobe — a small collection of versatile, interchangeable pieces that removes the daily "what do I wear?" decision entirely. The idea was popularised in the 1970s by London boutique owner Susie Faux, but the psychology behind it is backed by decades of research.
The next time you can't decide what to have for dinner at 8pm, you're not lazy. You've just used up your 35,000.