We are right on the cusp of downsizing - in fact, we are just back from a weekend break in the city we want to move to.
A few reasons..... we are suddenly rattling around in the house after 3 x DCs have moved out. The design of the house means it is painfully obvious that half of it is completely unused at the moment. Current house is expensive to run, and the garden is annoyingly big. Also, it has dawned on us that we want to be a bit more in the thick of things, have cultural stuff on the doorstep, places we can walk to etc etc.
However, the main driver for this is we really want to retire in the next couple of years, but still have 8 years left on our mortgage, so we really need to pay that off.
Fortunately, we live in a very expensive Surrey village and are planning to move to a cheaper area, so I'm hoping we don't need to compromise too much. Ironically, the current house is a bungalow, and the next one probably won't be....
As to where the DCs would stay....well, we would plan to still have 3 bedrooms. No grandchildren yet, but envisage adults in the bedrooms, GC on camp beds in the living room - we did this ourselves back in the day. Or B&Bs/hotels once they can afford it (another reason to live in a city). Neither of the DDs live far away, although DS is moving abroad later in the year.
I'm certainly not going to maintain a massive house just for a few days at Christmas, and I don't love my current house enough for it to be "forever". I am a bit of a hoarder, though, so feeling slightly sick at the thought of all the decluttering needed.
DM is 80, healthy for now, and still on her own in a 4-bed house, and is horrified by the concept of moving anywhere else. DDad likewise - but he has terminal cancer and has recently had to put a stairlift in his house as mobility is declining. He and DSM are busy doing Swedish Death Cleaning, bless them, but just have so much "stuff". Neither can quite understand why we would want to do this.