I can't imagine moving into anywhere smaller at the moment, to be honest. We don't live in a large house, by any stretch of the imagination, but it has enough space to enable DH and I to follow our own interests as well as be together. My only concern would be if the stairs became difficult to manage, but they are reasonably shallow and are in 3 sections rather than one steep stair case, so are fine at the moment. I'm not sure if a stairlift could be fitted to this style of staircase, but it would be something to be investigated if the need arose. Moving house entails a lot of upheaval, stress and expense, so I'm really hoping we never have to move. We are lucky to have friendly neighbours, the area is nice and there is a regular bus service on the doorstep and a rail service within easy reach to take us further afield (once this Covid is done) and shops and facilities are within walking distance or a short drive/bus journey away. Our garden is small but manageable and a young gardener comes to lower the hedge and prune magnolia for us, as they are the only things that are more difficult the older we get - the will is there, the energy isn't! (Also, he takes all the cuttings away which is a huge plus). ?
So, all in all, I'd be very sad to have to leave, and hope the day never comes.