Our older two girls shared a room for as long as was comfortable for them, which was until about a year ago. At their biomom's house, they still share a room. 9 times out of 10, one of them climbs in to bed with the other, waking both of them up, and they're total pills the next day from lack of sleep.
They also have no privacy, no separate space (shared closet, dresser, bookcase, desk, etc) and are miserable.
We were in a position to be able to find a house with 5 bedrooms. When we moved in, DD1 and DD2 still wanted to share a room. Within a few months of moving, they decided they (and we, because of the whole "waking each other up" thing) were done sharing a room so they've had their own rooms ever since.
DD3 wakes up at 6am, without fail, and DS sleeps until 8 or 9 if undisturbed. They too have separate rooms.
We're looking at a 6 BR house now, but the largest bedroom will become a big playroom.
Do kids deserve their own room? No. Can it make life abundantly easier? Abso-frickin-lutely. We've followed our kids' lead on this, so when they're ready to be split up (or share) we try and accommodate that.
I wouldn't ever consider separate sleeping quarters (because that's all bedrooms are in our house) to be important enough for us to go in to bankruptcy. We're lucky enough to live in an area in which we can get enough BRs for everyone to have their own (even when baby arrives) and be moving in to a better school district, for $67K LESS than the house we're in now.