In 2009, Joshua Fields Millburn’s mother died and his marriage fell apart. In the same month.

“These two events forced me to look around and take an inventory of my life,” Millburn said, “and really question what had become my life’s focus.”

His life’s focus came into sharp focus after he flew from Ohio, where he lived at the time, to Florida, where his 65-year-old mother had lived until succumbing to lung cancer. Once there, Millburn sifted through the stuff crammed into his late mother’s one-bedroom apartment: antique furniture; old paintings; numerous doilies; mismatched plates, cups and bowls; towels, sheets, blankets and quilts; and even 14 winter coats.

After reserving a U-Haul truck to haul his mother’s belongings to a self-storage unit back in Ohio, Millburn came across four boxes tucked underneath his mom’s bed. The boxes, each identified by a number written in black marker and sealed with packing tape, contained Millburn’s school paperwork from his time in first through fourth grade. It then dawned on him that his mother was clinging to memories by keeping those paperwork-filled boxes, but she hadn’t bothered to glance at the papers inside them in quite some time.

That’s when Millburn experienced an ah-ha moment: “Our memories are inside of us. Mom didn’t need to keep boxes to have those memories.”

The ah-ha moment spurred Millburn’s eventual transition from six-figure-earning consumerist to devoted minimalist, a transition he recounted recently at the annual conference of the National Association of Professional Organizers (NAPO). Today, Millburn writes and speaks about minimalism as half of the duo behind He and longtime friend Ryan Nicodemus espouse the virtues of leading a meaningful life with less stuff to weigh you down.

Here are four lessons Millburn, who now leads a meaningful and simple life in Montana, shared with the NAPO audience.

1. One Woman’s Trash Is Another Woman’s Treasure.

Joshua Fields Millburn and Ryan Nicodemus
Joshua Fields Millburn (right) and Ryan Nicodemus.

Following his ah-ha moment, Millburn canceled the U-Haul truck and the storage unit, and decided to sell or donate most of his mom’s belongings. Rather than selfishly hanging onto the bulk of his mother’s possessions, he found new homes for them over the course of 12 days.

“The truth is, by letting go, I was able to add value to other people’s lives,” Millburn said. “Just because I wasn’t going to get value from a particular item, that doesn’t mean that someone else wouldn’t get value from that item.”

Millburn did save a few items with sentimental value, such as an old painting and a few boxes of photos.

2. Less Is More.

Millburn has gained more joy by keeping just a handful of sentimental items rather than a bunch of them.

“For me, I get far more value out of the few sentimental items that I kept—and I’m actually able to use and display and enjoy—than if I would have watered them down with dozens or even hundreds of sentimental items,” he said.

3. A Picture Is Worth a Thousand Memories.

Before Millburn let go of most of his mother’s belongings, he took photos of some of them so that he could preserve the related memories. He also scanned and digitally stored many of his mom’s old pictures.

“While it’s true that our memories are not in our things, it is also true that sometimes our things can trigger the memories that are inside us,” Millburn said.

4. Decluttering Goes Beyond Stuff.

When Millburn—energized by the purging of his mother’s belongings—began his journey as a minimalist, he vowed to get rid of one material possession each day for a month. “The result: I unloaded way more than 30 items in the first 30 days—like way, way more,” he recalled.

As he sifted through items in the rooms, closets, cabinets and hallways of his home, Millburn pondered each “artifact” and asked whether it truly added value to his life. If it didn’t add value, then Millburn banished it from his home; he emptied out many of his clothes and almost all of his DVDs.

“The more action you take,” he said, “the more you want to take action.”

During an eight-month span, he wound up shedding about 90 percent of his possessions. As Millburn immersed himself in minimalism, he felt freer, happier and lighter. He’d decluttered his space as well as his life, enabling him to more deeply appreciate his relationships and his passions.

“As a minimalist, every material possession I own serves a purpose or brings me joy,” Millburn said.

Check out our room-by-room guide to decluttering: