I really don't know.
On the one hand I never wanted the worry of what to do if we fell on hard times and couldn't afford to make mortgage payments, so we bought a small house. That still feels like the right choice.
But we remained crammed into the little house for far too long because I couldn't face the upheaval of moving and thought the house was okay for us. We weren't miserable. However, the minute we moved into a bigger house with a garden I discovered what we had been missing.
My 9yo began enjoying loads of time outside because she could. I had thought she "wasn't outdoorsy" because she hadn't seemed bothered whether she was in or out. Turns out I was wrong. There was space to set up a tent and camp in the garden. We could sit outside. It's lovely. She could also spread out a craft project indoors for a few hours without having to clear up because people were tripping over it.
My teen could have friends over. They could even sleep over, which had only been theoretically possible in our two-up two-down. We could have a couple of people come for dinner and get everyone round the table.
It became possible to have a private conversation without doing it in whispers, just by going upstairs and shutting a door. I sleep better because we're more spread out and there's less noise from other people watching TV, using the loo, cooking and showering. The neighbours are farther away and as we have a semi instead of a mid-terrace, there's only one set of neighbours, so it is quiet. And we make as much noise as we want when they aren't home!
All little things, but we have a better quality of life.