Our house, not counting the attic and unfinished portion of the basement, is about 3500 square feet, on a little more than an acre of land. I love it. The size is big enough so that, across three levels, it has never seem crowded when the kids were growing up and when we have had family and friends over. We bought it from the family that built it, and they built it solid and with oversize rooms. Even during times when lots of people are here, one can always find a quiet spot in the house or the property to relax. The other nice feature is the view - across the road from us is nothing but farmland, on clear days we can see a distance mountain range, and the houses are farm enough apart that we can enjoy the backyard with our neighbors encroaching on us, and vice versa.
DW and I spent most of our years before college growing up in, or bordering, the inner city. After we married we hoped one day to live in a place like we have now. When we first looked at the house, DW turned to me and said "this is the house I saw in my dreams when I was a kid". The asking price was out of our affordability range, but we made an offer that was within our range (about $70K less than asking price) - and, due to the circumstances at the time, it was accepted. That is another reason we love this house.
We have had chances to move into even bigger houses, and some of our friends have houses larger than us. With things like bowling alleys, 16 seat movie theaters, large pinball/video game rooms, etc. But we never felt envious, and we both felt that a house bigger than this would also mean a lot more work and expense. The mortgage was such that it was not dependent on DW having to work, and we wanted to keep that flexibility. I recall, at the peak of the market here before the Great Recession, realtors calling and showing up unsolicited wanting to put our home on the market - but, as DW wisely stated, "but where would we live? Bigger, yes - but more expensive? Why?"
The only real challenge now is reducing clutter - 35 years in a house raising kids, and having my wife love to keep and collect things, can make de-cluttering a challenge. Having a big house can hide some of that cluttering. Some of this is on me, as what I consider uncluttered many would consider "bare"

. But we are working it out.
We hope to stay here as long as we can, and right now we have no mobility issues. But the future is unknown, and we have discussed "what-ifs" and options. But for now, we are going to enjoy this house for as long as we can.