We have been "practicing" living in a smaller space for 7 winters. Our winter home is 400 square feet, with a covered but not enclosed patio and an 8x10 shed. No attic, no basement, no stairs. It is a simpler life - fewer appliances, buy as needed and use up, an item must be carefully planned for, usually another possession must leave. We share large items and seldom used ones with friends and neighbors - for example, there is a "roving party tote" of serving pieces, trays, pitchers and misc., along with an ice bucket & large cooler shared among about a dozen households. There is one community lawn mower, and one weed whacker. Very freeing, actually.
I find when we return to our "big" house - 1300 sf on 2 levels plus a garage & sheds, I am overwhelmed by the amount of stuff - I spend at least an hour or two nearly every day getting rid of things we no longer use or need. Last week several generations of weed-eaters, leaf blowers and hedge clippers, all replaced by a few lightweight battery operated tools, went to a fund-raiser sale along with no longer used decorative pots. Dozens of smaller pots, filled with plants I thinned, went along. Saturday, boxes of no longer used electronic gear went to our community recycle day. Today I filled a recycle bin, a box for the scrappers, and a large trash bag just from a few shelves in the garage, making space for items that were piled on the workbench or floor.
Following the model taught by my parents, I'm trying not to leave a big job for my busy kids! My goal, by this October is to have at least one empty shelf in each cupboard, free space in every closet, and no more "mystery boxes" on high shelves.
I figure even if we stay in the same place, we can condense and simplify to make life more relaxed. Now I just wish manufacturers would make affordable furniture for small spaces. Those huge sectional sofas don't begin to fit my 12 x 16 living room.
We too had a big house, with lots of kids. Now, just the two of us, we find that the heavy furniture we used to choose ("it'll last longer with the kids jumping on things")... we bought light furniture, a lot of IKEA things. Neither of us is that strong anymore to be lifting things.. I am 81 and he is 76 and diabetic. One of those new vacuum cleaners such as Dyson or Eureka is a big help, the ones that are just one wand and actually quite powerful. Much easier. Now my son suggests that we have a housekeeper just once a month to do the heavy cleaning.