Twins at 12 Months: Convertible Seats, First Shoes, and the Big Resale

Twelve months with twins means two convertible car seats, a bottle wind-down on two timelines, and the biggest resale batch of the year. It also means one baby may be walking while the other is still cruising the sofa, so the shoe question arrives twice and out of sync. Here is the gear that retires, what replaces it, and how to turn a year of twin gear back into money.

What changes at 12 months#

Walking, for some. The typical range is wide, and twins born early are tracked on adjusted age, so one walker and one crawler at the first birthday is normal and not a comparison to run. Feeding shifts: most pediatricians move babies from formula to whole milk around now, and the bottle-to-cup transition starts, which with twins usually means two separate timelines because one drops the bottle in a week and the other clings to it for months. And the infant car seats are done, if height didn't end them earlier. Both babies out of infant seats and into rear-facing convertibles is the big purchase of the month.

Gear that retires#

• Infant car seats, both. Height limit, weight limit, or the first birthday, whichever came first. Rear-facing convertibles from here.
• Formula and the formula pitcher or machine. The Baby Brezza that ran twelve times a day is now a countertop ornament. Sell it; there is always another twin family two months from needing one.
• Bottles, gradually. Do not throw them out on the birthday. One twin will need them for weeks longer than the other. Retire half the stack now, the rest when the second baby is done.
• The play gym, jumper, and any bouncers that survived nine months. If they're still in the house, they're storage.
• 9 to 12 month clothes, and anything a walker can't move in. Footed sleepers with grippy soles start earning their keep.

Gear that arrives#

• Convertible car seats: buy two, new. The Graco Extend2Fit at around $200 each is the value pick with a long rear-facing leg-room panel. The Graco SlimFit or the Diono Radian 3RXT if you need two seats plus an adult, or three across, in a sedan. The Britax Marathon ClickTight if you'd pay around $330 each for an install that's hard to get wrong, which with two seats is worth something. Same model twice, so you learn one install.
• Walker sleep sacks: buy two per baby once they're walking. The Kyte Baby Sleep Bag Walker has leg holes so a standing toddler doesn't trip in the crib. The non-walker stays in the regular sack until they're up.
• First shoes: buy one pair per baby, when that baby walks outside, not before. Barefoot or socks indoors. Get each baby measured; twins are rarely the same shoe size even when they wear the same clothes. Do not buy matching pairs in one size.
• Cups: buy four of whatever open or straw cup you're using. Two per baby, because one is always in the dishwasher and the other is under the sofa.
• Boosters at the table: maybe. If you bought Antilops or Tripp Trapps, you're set for years. If you bought SpaceSavers, they convert. Do not buy new seating for the birthday.
• Skip: a new stroller. The double you bought at six months lasts until they walk long distances. Skip a wagon until they're 18 months and sitting reliably. Skip the twin harness leash, still. Skip toys sized for the birthday; the grandparents have that covered in a way you cannot control.

The big resale#

Twelve months is when a year of twin gear is worth the most it will ever be, because the next twin family is shopping for exactly the pile in your garage. What to list, and how:

• Infant car seats: honest answer, the resale market is thin. Seats have expiration dates and buyers cannot verify crash history. If yours are unexpired and never crashed, a multiples group may take them at a low price; otherwise, a retailer trade-in event gets you a coupon and keeps them out of a landfill.
• The formula machine, bottle warmer, sterilizer, and drying rack: list as a feeding bundle. They sell fast to expecting twin parents.
• The double stroller, if you're upgrading or done: strollers hold value best of anything. Clean it, photograph it open and folded, and list it with the model year.
• Bassinets, swings, bouncers, play gym, jumpers if any are still around: twin pairs sell as pairs. Price them together at slightly under two singles.
• Clothes, sized and bagged as twin lots, by season. A bag of 24 matched 9 to 12 month pieces sells; 24 individual listings do not.

Where: local multiples clubs first, because the buyers are pre-sold on twin gear and you skip the shipping. Then general marketplaces. Consignment sales run by twin clubs twice a year are worth the wait if the timing lines up.

What we'd do#

Buy two Extend2Fits (or two SlimFits if the car is small) the week one twin hits the infant seat limit, and install both the same afternoon. Keep half the bottles for the slower baby and sell the formula machine now. Measure feet only when a baby is walking outdoors. List the feeding bundle and the bassinet-swing-bouncer pile as twin sets on the multiples group. Then bank the money, because two of everything comes back around at the toddler bed stage.

Related reading#

• Twins at 9 months: crawling, gates, and the playpen question
• Twins turning one: what changes and what gets easier
• Twin gear resale guide
• Weaning twins off bottles: two timelines or one