If you have kids, you already know the dirty secret of parenthood: the real money pit isn’t the diapers or the daycare. It’s the sports cleats that fit for six months, the art supplies that evaporate in a week, and the musical instrument your tween swore they’d love forever. Kids’ interests change faster than their shoe size, and retailers know it. But with a little foresight and a willingness to buy used at exactly the right moment, you can keep your kids happily busy without subsidizing a second mortgage for the big-box stores. The trick is to stop shopping like you’re buying for a static adult and start shopping like a scout for a moving target.

For the toddler set, ages one to four, the battle is all about gross motor chaos. They want ride-on toys, balance bikes, and anything that makes noise. Here is your golden rule: never buy new. Toddlers destroy things with the efficiency of a demolition crew, and their attention spans are shorter than a TikTok video. Hit local consignment sales and Facebook Marketplace for gently used plasma cars and wooden train sets. Resale prices for this age group are absurdly low because every parent is desperate to clear out the garage. One specific tip: buy winter gear in April and summer gear in September. Thrift stores are overflowing with puffy coats when the weather turns warm, and you can stock up two sizes ahead for pennies on the dollar. Just resist the urge to pull them out early when a cold snap hits in October—your toddler will be fine in a layer of fleece, and you’ll be grinning when you remember the six-dollar parka waiting in the closet.

Once elementary school hits, the game changes. From ages five to nine, kids develop real opinions, but they also grow out of everything between Labor Day and Valentine’s Day. This is the stage where you need to master the art of the seasonal shift. For team sports like soccer or baseball, the absolute cheapest window for brand-new gear is the week after the season ends. Retailers slash prices on cleats, shin guards, and gloves by 50 to 70 percent because they need shelf space for the next sport. Buy for next year, but only if you know the correct size. That sounds obvious, yet parents routinely guess wrong. Instead, check your kid’s foot growth over the past year and add one full size for the next season. If you get it wrong, you can always resell—you’ll still come out ahead compared to paying full summer prices.

Elementary age also brings the hobby explosion. Your seven-year-old wants to paint, your eight-year-old wants to do robotics, and your nine-year-old suddenly begs for a keyboard. This is where you need to make a distinction between a fleeting whim and a genuine passion. A rule of thumb: for any hobby that requires a big-ticket item, let the kid wait six weeks while using a borrowed or cheap version. If they still care after six weeks, then buy used. Musical instruments are the biggest trap. A brand-new beginner violin can run two hundred dollars, but a used one from a local shop or online marketplace often costs half that and holds its value. The same goes for art supplies—buy the professional-grade stuff only after they’ve gone through three cheap sketchbooks. And for hobbies like swimming or gymnastics, the real expense is the classes, not the gear. Look for community center programs instead of private academies, and always ask about sibling discounts or semester-long commitments that lower the per-session rate.

Now we get to the tween years, ages ten to fourteen, where expenses escalate because the kids get taller and their tastes get pricier. This is the age of specialized sports like lacrosse, track, or competitive club volleyball. The best strategy here is to lean into the exchange economy. Cleats and running shoes are the worst offenders, but they also have a robust secondhand market because kids outgrow them long before they wear them out. Look for “like new” pairs on resale apps, and don’t be afraid to ask about the original purchase date—most parents will disclose that the shoes were worn for one short season. For club sports, the registration fees are non-negotiable, but you can save on equipment by renting through the organization or buying last year’s model. And here is a pro tip: when your tween insists they need a fifty-dollar mouthguard because the orthodontist recommended it, ask the orthodontist’s office if they have any brand they stock. Often they’ll give you one free or let you purchase a basic version for a few bucks.

The tween years also bring the greatest gift of all: the ability to understand value. Sit down with your kid and show them the price difference between a brand-new tablet and a certified refurbished one from the manufacturer. If they’re passionate, they’ll get on board. For less expensive hobbies like gaming, teach them about buying used controllers and waiting for end-of-season sales on popular titles. This isn’t cheapness—it’s financial literacy. Your child will eventually leave your house, and knowing how to wait for a deal is a survival skill. So as you navigate the ages and stages from squeaky toys to eleven-inch feet, remember that the goal isn’t to deprive your kids. It’s to put them in the best gear possible without making their hobbies your personal donation to corporate America. Shop used first, time your new purchases against the seasons, and never, ever pay retail for something they’ll outgrow in three months. Your wallet will thank you, and your kids will still have a blast.