One in, one out. That’s the sustainability rule esteemed rocket scientist and doctor Anita Vandyke, MD, creator of the popular Instagram account @rocket_science, swears by for avoiding overconsumption.

In an Instagram post, Vandyke references the common saying that’s meant to help people curb the temptation to give into overconsumption. The rule fosters more of a minimalist mindset, which in turn helps out the environment. After all, one of the best ways to lessen your environmental impact is to simply buy less.

How exactly does the “one in, one out” rule work? Simple: If you bring one new item into your home, then you must get rid of one. (But don’t send that old item straight to the landfill by tossing it in the trash. Find somewhere to donate it, or ask a friend, family member, or neighbor if they could use it.)

“It’s tempting to fill your homes with thrifted finds because they seem like such bargains, but this is a gentle reminder to be mindful of overconsumption and overloading your home,” says Dr. Vandyke. “That’s why I have a general ‘one in, one out’ rule in my home. I live in an apartment with a toddler, so we don’t have any room for any extras. This means if something comes in, we have to let something go.”

When it comes to overconsumption, you might not even realize you’re doing it. After all, it’s really easy to accumulate, accumulate, accumulate. Eventually, all that stuff outgrows the space and gives way to clutter. According to Dr. Vandyke, though, living by this rule can really help you take charge of your consumption.

“Applying this rule has helped maintain my minimalist home,” she says. “It’s also saved us money, as it makes me question every purchase.”

It’s not just about living minimally. If you live by the “one in, one out” rule, you’re more likely to question each of your purchases, better registering whether it’s really worth the cost. You’re forced to ask yourself, “Is this new purchase worth letting go of something else in my home?”

If the answer is “no,” you might find yourself saving money and accumulating less stuff—stuff that eventually has to find a new home or go to a landfill at the end of its life anyway.

Eco-minimalism, Minimalism, Overconsumption, Thrifting