Trond Nesse - Publisher, Earning One

Sell What You No Longer Use — Then Invest the Money

Most households have a quiet financial leak hiding in plain sight.

Children outgrow clothes, bicycles, toys, sports equipment and electronics. Adults replace phones, furniture, tools, hobby equipment and household items. Much of the old stuff gets pushed into a closet, garage or attic until its resale value is nearly gone.

There is another option:

Sell it while it still has value — and invest the money.

The individual amounts may seem small. $40 for a jacket. $75 for an old bicycle. $150 for a phone. $25 for a box of toys.

But the interesting number is not what those items are worth today.

It is what those dollars could become after decades of compound growth.

Americans buy — and discard — a lot of stuff

The average U.S. consumer unit spent $78,535 in 2024, according to the Bureau of Labor Statistics. That included about $2,001 on apparel and services and $3,609 on entertainment.

Families with children face another steady stream of purchases.

For the 2026 back-to-school season alone, the National Retail Federation estimates that families with K-12 students will spend an average of $863.86 on clothing, shoes, school supplies and electronics. Total U.S. K-12 back-to-school spending is expected to reach $43.3 billion.

That is only one shopping season. It does not include birthdays, Christmas, bicycles, sporting equipment, toys, furniture, gaming equipment, phones or everything else children grow out of.

A large amount of material eventually reaches the waste stream.

The EPA's latest comprehensive material dataset remains based on 2018 data. It estimated that Americans generated about 13 million tons of end-of-life clothing and footwear, with roughly 9.1 million tons going to landfills. EPA specifically notes that reuse and resale happen before these items enter its waste statistics.

The opportunity is simple: capture some of that value before it disappears.

Secondhand is already mainstream

Selling used belongings is no longer unusual.

OfferUp's 2025 Recommerce Report found that 93% of surveyed Americans had bought something secondhand during the previous year and 54% had sold a used item. The report also found that clothing represents only about 25% of the resale market. Furniture, electronics, tools, sporting goods, car parts and baby and children's items make up much of the rest.

Among sellers surveyed, 28% said they used resale earnings for future goals or investments.

eBay reports something similar: 86% of its surveyed sellers source inventory from their own belongings. In other words, you do not need to become a professional reseller. For most people, the inventory is already sitting inside the house.

The financial idea behind this guide is simply to change what happens to the money after the sale.

Instead of:

Old stuff → cash → new spending

use:

Old stuff → cash → investment

The Sell-and-Invest Rule

Create one household rule:

If we no longer need it and it still has resale value, we sell it. The money goes directly into investments.

The important part is the second sentence.

If a $100 sale lands in the checking account, it is very easy for that $100 to disappear into groceries, takeout or another purchase.

Instead, treat resale income as money that never belonged to the household budget.

Transfer it directly to a separate investment account.

You can even name the account something visible such as:

Things We Didn't Throw Away

That turns decluttering into a measurable financial project.

What could this become for a child?

There is no reliable government statistic telling us the average amount parents could recover by selling everything a child outgrows.

So the responsible approach is to use scenarios rather than pretend there is a national average.

Assume a parent sells clothing, toys, bicycles, sports equipment, electronics and other items the child no longer needs and invests the net proceeds after selling costs.

For the examples below, we use a 7% average annual return.

Investor.gov explains compound growth and uses 7% in one of its own long-term investing examples. It also notes that some experts use roughly 7–10% as a historical planning range for diversified long-term U.S. stock investments. Actual future returns are unknown and can be substantially lower or negative for long periods.

From birth through age 18

These numbers assume contributions at the end of each year and 7% annual compound growth.

They are future nominal dollars, not today's purchasing power, and they do not account for investment taxes, account fees or inflation.

But they demonstrate something important.

A family does not need to find thousands of dollars at once.

At the $500-per-year level, the family has contributed only:

$9,000 over 18 years.

Yet the account could be around $17,000 by age 18 under the 7% assumption.

Then something much more powerful happens.

Time takes over.

If the child never adds another dollar and the $17,000 simply remains invested from age 18 until 65, the model reaches roughly:

$409,000.

The original source of that money?

Clothes that no longer fitted. Old bicycles. LEGO. Gaming equipment. Phones. Sports gear. Toys. Furniture. Things that could otherwise have ended up forgotten in a garage.

Return assumptions matter enormously

A 7% return is not guaranteed.

To show how sensitive long-term projections are, use a lower 5% return for the same $500-per-year child example.

At 5%, $500 invested annually for 18 years becomes roughly:

$14,100 at age 18.

If that money then remains invested until age 65, it becomes approximately:

$139,000.

That is far less than the $409,000 result produced by 7%.

But it is still a remarkable result considering that the original contributions totaled only $9,000.

This is why long-term financial projections should always show their assumptions.

What about an ordinary adult lifetime?

The same idea works without children.

Consider someone who starts at age 25 and simply sells things they no longer use.

The amounts do not need to be impressive.

At a 7% average annual return:

Someone investing just $50 per month of resale proceeds from age 25 to 65 contributes $24,000 of actual cash.

Under the 7% assumption, that could grow to almost:

$120,000.

At a more conservative 5% return, the same $50-per-month habit would produce approximately $72,500.

Again, the point is not that everyone will achieve these exact returns.

The point is that seemingly insignificant household items can become meaningful financial assets when money is repeatedly redirected from consumption into ownership.

Start with the items that lose value fastest

The best time to sell many products is not when you finally decide to clean the garage.

It is when you stop using them.

Electronics are an obvious example. A previous-generation phone may still have meaningful resale value today and very little several years from now.

The same principle applies to children's equipment.

A bicycle that has become too small is not becoming more useful while sitting in storage.

Neither are football boots, skis, gaming consoles, tablets, jackets or toys the child has stopped playing with.

A practical household routine is:

1. Identify items that have not been used recently.
2. Check realistic completed-sale or marketplace prices.
3. Sell higher-value items individually.
4. Bundle low-value children's clothing or toys.
5. Donate items whose resale value is too low to justify the time.
6. Transfer the net sale proceeds to the investment account immediately.

This avoids another common mistake: spending two hours trying to sell a $5 item.

Your time has value too.

The 30-day rule

There is another useful rule for preventing garages and closets from filling again:

Once an item is replaced or outgrown, decide its future within 30 days.

Keep it. Sell it. Give it to someone. Donate it. Recycle it.

But avoid the default option:

store it indefinitely.

Resale value usually declines while the item is sitting unused.

Turn consumption into an asset cycle

The idea becomes even stronger when buying decisions change too.

Before purchasing something expensive, ask:

What will this probably be worth when we are finished with it?

A $600 bicycle that can later be sold for $300 has a very different lifetime cost from a $400 bicycle that becomes nearly worthless.

Purchase price: $600

Later resale: $300

True ownership cost: $300

If the $300 resale proceeds are then invested rather than spent, the economics improve again.

Thinking about resale value before buying can therefore influence which brands, materials and products you choose.

Durable products with healthy secondhand markets can sometimes be cheaper to own even when their initial purchase price is higher.

Create a family resale account

For families, this can become a surprisingly useful financial lesson.

Let children see the process.

A bicycle they no longer use sells for $150.

Show them the $150.

Then show them where it goes.

Instead of teaching only:

work → earn → spend

you are demonstrating:

own → maintain → resell → invest → grow

The lesson may eventually be worth considerably more than the bicycle.

Where should the money be invested?

This guide does not recommend a particular fund.

For long time horizons, many investors use diversified, low-cost index funds rather than trying to select individual stocks.

The important principles are diversification, low costs and an investment strategy appropriate for the person's time horizon and risk tolerance.

Money needed within the next few years should generally not be treated the same way as money intended to remain invested for several decades.

Different account types also have different tax and ownership consequences.

For a child's money, parents may consider taxable accounts, custodial accounts or education-focused accounts depending on what the money is ultimately intended for.

The investment account should be chosen deliberately rather than simply selecting whatever produces the highest historical return.

A note about taxes when selling used items

Most ordinary household items are sold for less than their original purchase price.

The IRS says that when a personal item is sold for less than the owner paid for it, there is generally no tax liability on the sale, although the personal loss is not deductible.

If a personal item is sold for more than its cost basis, however, the gain can be taxable.

Online marketplaces and payment processors can also generate reporting records such as Form 1099-K, so keeping reasonable purchase and sales records is useful.

This becomes particularly important for collectibles or items that increase in value.

The bigger idea: stop treating used things as worthless

A household contains two kinds of assets.

Financial assets are obvious: cash, stocks, bonds, retirement accounts.

But households also own thousands of dollars of physical assets: furniture, electronics, tools, sports equipment, clothing, toys, bicycles, appliances, hobby equipment.

Normally these assets gradually depreciate until they are discarded.

The Sell-and-Invest approach attempts to capture some remaining value before it reaches zero and convert that value into an asset that has the potential to grow instead.

You are effectively moving money from a depreciating asset into a potentially appreciating asset.

Repeated for decades, that small behavioral change can become surprisingly powerful.

FAQ

The bottom line

The idea is not really about decluttering.

It is about recognizing that discarded value can be converted into invested capital.

A family investing only $500 per year from things a child no longer needs contributes $9,000 over 18 years.

Under a 7% compound-growth assumption, that could become about $17,000 by age 18.

Leave it invested long enough and the mathematics becomes much more interesting.

The next time you are about to put an old bicycle, phone, jacket or game console into permanent storage, ask a different question:

What could this become if I sold it today and invested the money instead?

That question turns old stuff into something most households rarely see when cleaning the garage:

future wealth.