What is the 20/20 rule?

The 20/20 rule is straightforward: If you can replace something in under 20 minutes for less than $20, you don’t need to keep it. (Homes and Gardens)
Individuals often struggle to part with items, thinking they might need them one day. People keep items just in case they come in handy in the future.
This might be well and good if you have a huge house and loads of storage space, but for most of us, ‘just in case items’ are nothing but unnecessary clutter.
The Minimalists, two childhood friends, authors, and podcasters—Joshua Fields Millburn and Ryan Nicodemus —came up with the 20/20 rule to combat the habit of keeping just-in-case items.
The rule suggests that if an item costs £20 or less and can be replaced in under 20 minutes, you can let it go. ‘Think $20 in 20 minutes.’ (Homes and Gardens) People who have tried this method report that, in most cases, they have had to replace fewer than a handful of items over the past five years. The Minimalists echo this sentiment:
Although we’ve rarely had to replace a just-in-case item (fewer than five times for the two of us combined), we’ve never had to pay more than $20 or go more than 20 minutes out of our way to replace the item. This theory likely works 99% of the time for 99% of all items and 99% of all people—including you. (Getting Rid of Just-in-Case Items: 20 Dollars, 20 Minutes)
Unless it’s sentimental items or items that are very expensive or hard to repurchase, allow yourself to let go of anything you don’t need to free up space in your house. In today’s world, it is easy and quick to replace items.
But what I love most about the 20/20 rule is its practicality. I tried the KonMari method. I actually held a hammer in my hand, trying to decide if it “sparked joy.” Honestly, it was just too wishy-washy for me. The 20/20 rule has allowed me to set time and distance guidelines: “I don’t think I’ll need this blue nail polish anymore, but I know I can get a new bottle for about $6 at the drugstore five minutes from my house if I do.” Simple. Measurable. Lovely. (Apartment Therapy)