Twins require a lot of stuff. I mean all babies do (to the extent you want/choose to buy/have stuff, I know you COULD get buy with nothing but a car seat and a crib), but there is just so much stuff. Assuming you live "normally" and not in a 400 sqft cabin, you need 2 car seats, 2 cribs, 2 high chairs, and a double stroller. And then there is the nice to have stuff - 2 baby containment devices at minimum for little guys and 2 more for bigger babies, a playmat, a pack and play, a single stroller, a dresser, a changing table, toys. We have a small house, and honestly, all their stuff takes up a lot of space, and I think we're relatively minimal.
- 2 travel swings and a bouncer (none of which got a TON of use, but the bouncer was pretty popular for its lights. They never were into the vibration). And two Boppies.
- 2 exersaucers and one of those jumper things that hangs from the doorway
- 2 space saver highchairs (which still require chairs, but the footprint is smaller than a normal high chair, and they convert to boosters - sometimes I think the ones that clip on the table would be nice but its nice to face both babies to you...or the computer to Skype or the TV to stop crying).
- 2 infant seats (you could, in theory, skip these, but I can't really contemplate the logistics of moving two floppy babies in and out of the car without them) and now 2 convertible seats (the infant seats are still used sometimes and live on our enclosed porch). Oh, and a baby carrier. We have an Ergo (love) and a Moby (ok).
- a double snap and go (again, could skip, but this thing was FANTASTIC when they still slept all the time and was so nice for going anywhere in the winter), a double Bob, a double umbrella stroller. The post also made a good point about the selection of double strollers. It isn't the same as singles. They're much bigger in general, and the ones that aren't sacrifice something (eg, the City Select is pretty tight for two bigger toddlers, one baby gets a view of a back in the Phil & Ted, the City Mini double is quite wide folded AND needs two hands unlike its singleton counterpart.)
- and the toys. People keep giving us toys. This is awesome, but man there's a lot of them. And they already fight over them. Nevermind that we have two cars and two copies of some books. They want the same one.
- then there is the dozen of bottle parts. And now food containers. and the clothes and diapers. All takes up space.