Prams !!

I know there are some companies that have pushchairs that are one but can be adapted for two when the time comes. I sadly can't remember which these are as it's been almost a year since I got mine, but it would be worth looking into.

We planned this, I’d say, get a single stroller, but just get something simple and cheap, or go for something nicer, but try and get second hand. (I got a single but spent too much. I’d just feel silly getting a double in case I didn’t get pregnant again at all, or it took ages)

Then get a decent double when you your second arrives. We have a mountain buggy duet and it’s so good, the out n about nipper is great too.
I found the double decker types unstable, especially on rough ground or going up curbs. And the bugaboo donkey is enormous in double mode.