We go back and forth about downsizing in the future. My wife is 57 and I will be 50 in six weeks. Older kids in 30's are on their own but we still have boys in 10th and 12 grades. I can get a retirement at 70% of my salary at 55 with option to buy subsidized healthcare. We always thought about moving to Palm Springs in retirement in a 1200-1500 SF place and being able to lock it up and travel for a month or three at a time. We do recognize that we change with time. Our older kids (hers) might move here and need to spend some time with us while looking for a place, the younger ones might also, you can't tell. We may end up living near whichever kids have our grandchildren to help raise them. Who knows. We do know that 2400 SF that we have now is more than our needs, but with that we get a large yard which we love and can be away from children but still be under the same roof.
Time will tell.