This is the other main thing to look out for in a stroller for twins, and in my opinion the main thing. After all, there's nothing worse than going on long journeys and being uncomfortable. We've all been on a plane without enough room, and that's miserable even if the destination is somewhere exotic and warm!
Look for deep seats that have a lot of mobility and space. The ability to recline is great, as are anything that you can adjust as your kids grow and get bigger, like footrests.
Finally, consider things like the sun and rain. Does it have a canopy or weather cover? Is it going to be big enough?
How simple is it to fold?
We'd all like to have infinite space but sadly that's not reality, and at some point you're going to want to fold your stroller back up. Even if it's just to throw it in the back of the car when you're travelling.
If you don't see yourself needing to fold your stroller up often, for example if you have a lot of garage space, then you can pay less attention to this, but it's still an important consideration.
The top strollers have systems built in that allow you to fold down and assemble them quickly, easily and with the minimum of fuss. Sometimes even using only one hand. And having a free hand is really useful when you've got young ones around right?
Is there enough storage space?
We touched on this, but on long journeys you'll be thankful to have enough space to empty your pockets and get that bag off of your shoulder, as well as dumping everything you might need into your stroller, and more.
Storage varies massively, with some strollers holding a decent sized shop and some only having enough room for a diaper bag and a few extras. More storage is generally better, so take it if you can find it.
Does it fit car seats?
This is becoming more and more popular, as baby travel systems get more and more advanced. It's at the point now that high end strollers allow you to take a car seat straight out of the car and lock it into place directly into the stroller, which is great if the current occupier happens to be taking a nap.
Not all seats fit into every stroller for twins, and some strollers might not have this option though, so it's something to consider.