"Just double everything" is the advice everyone gives, and it's wrong often enough to cause real problems. Some categories genuinely need two of the exact same item. Others need one purpose-built product designed for two babies at once, not two single-baby products used side by side. Getting this distinction right saves money and, in a couple of cases, actually matters for safety.
Every baby needs their own crib or bassinet, their own firm mattress, and their own car seat — this isn't a place to economize by sharing. Car seats specifically must be individually and correctly installed for each baby; a "two-for-one" car seat product doesn't meaningfully exist for safety reasons. Sleep sacks, swaddles, and crib sheets should also be doubled — sizing and safety fit matter per baby, and you'll be doing laundry constantly regardless.
This is the category most registries get wrong. A baby monitor is the clearest example: buying two single-baby monitors means juggling two separate apps and screens at 3am. A dual-camera or split-screen monitor built for two is a real quality-of-life upgrade, not a luxury. The same logic applies to play mats (a mat sized for one baby means constant territorial disputes once they're both mobile — a larger or extended mat avoids this) and, for breastfeeding or combo-feeding parents, nursing pillows — a twin-specific nursing pillow is designed to support feeding both babies at once, which a single-baby pillow simply isn't shaped to do.
Strollers belong here too: a side-by-side or tandem double stroller is a different product category from two single strollers, and the two styles have real tradeoffs — side-by-side is easier to see both babies but wider for doorways; tandem is narrower but one baby always has a less scenic view. Worth testing both in person before deciding, if you can.
Diaper pails, changing tables, diaper bags, bathtubs, humidifiers, white noise machines — one of these serves both babies fine. You'll want extra capacity in some cases (a bigger diaper pail, a diaper bag with more storage) but not a second unit. The same is true for glider chairs, bouncers, and swings in most cases, unless your specific routine has both babies needing to be soothed independently and simultaneously on a regular basis — in which case a second unit may genuinely earn its keep, but it's worth waiting to see if that's actually your reality before buying two.
Diapers, wipes, and formula (if applicable) will genuinely go faster with two babies, but not always at a clean 2x multiplier — bulk buying and subscribe-and-save programs often make more sense than doubling every individual box on a registry. This is one area where a slightly higher starting quantity on Must Have consumables, rather than a strict "times two" on every single item, tends to match reality better.
Before doubling anything, ask whether the category needs two identical items, one bigger/purpose-built item, or genuinely just one. It's a more useful lens than "multiply by two" for almost every category on a registry, and it's usually the difference between a twin registry that actually reflects two-baby life and one that's just a longer version of a singleton list.
Expecting multiples? Tell us, and we'll build a registry that knows the difference between "double it" and "get the twin version."
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