First, Zach Carlsen of Stillwater piled up every item of clothing he owned. Then he donated the mound of clothes that was 3½ feet high by 3 feet wide.

It was the start of Carlsen’s “Uniform Project,” where he ditched all his clothes — including his late uncle’s hat and the shoes he bought in Paris — in exchange for one simple outfit that he plans to wear every day for 365 days.

Now, three months into the experiment, he thinks he may continue a version of it past his original deadline.

“At the core of it was something really practical,” said Carlsen, a 36-year-old life coach. “But it has actually rippled out into my life in ways I could not have predicted. It’s been amazing and powerful.”

Even though many of the clothing items were like “small journal entries,” he said, he felt like they were anchoring him to parts of his past. Plus, deciding what to wear each morning was just one more choice that he said contributed to a kind of decision fatigue, draining energy from the big ideas and goals he wants to pursue.

To be clear: Carlsen isn’t wearing the same exact clothes every day, just the same outfit. His wardrobe consists of five pairs of gray pants, nine black T-shirts, four navy sweaters, 12 pairs of socks and 12 boxers. The only leeway he has left in his uniform is the choice of two belt buckles and four different pairs of shoes.

For Carlsen’s girlfriend, Charity Barlass, the uniform project didn’t come as a surprise. She’s used to Carlsen’s big ideas, including his recent book about an optimistic pancake with attention-deficit disorder. Yes, a pancake.

And the uniform?

“It was pretty similar to what he already wore,” she said, laughing.

Carlsen isn’t the first to adopt a limited wardrobe as a means to simplify. Apple magnate Steve Jobs always wore the same outfit — black turtleneck, bluejeans and sneakers. Facebook’s Mark Zuckerberg is typically seen in a gray T-shirt, jeans and a hoodie. Even Albert Einstein was known for favoring similar gray suits.

Carlsen got the idea from Matilda Kahl, a creative manager at Sony Music, who always wears the same outfit to work.

“I wanted to simplify and I didn’t know where to start,” he said. “So I started with my closet, and I found that to be a bite-sized piece I could get my mind around.”

Since committing to the uniform, he’s found that he’s more conscious of how he invests his energy in other parts of his life — mainly relationships, he said.

“I truly believe we are what we do every day,” he said. “So much of growth happens subtly and quietly over time, but it has this cumulative impact.”

Carlsen figures that even if the uniform saves him just five minutes of decisionmaking in the morning, it’s more than worth it. By the end of the year, that adds up to 30 hours spent doing something other than picking out what to wear.

There are other concrete advantages: laundry is quick and easy, as is packing to travel.

Though Carlsen knows that adopting a uniform isn’t for everyone, he said there’s a universal lesson in making a change and sticking to it. He said he often asks others: “What kind of little shifts could you make today that you do every day so the result would add up over time to make a big impact?”

Barlass isn’t shocked by the attention Carlsen’s project has attracted.

“I think a lot of people are looking for something like this,” she said. “I feel like he’s going to start a revolution.”