I’ve been told exactly this before, and it’s scary to hear because I know it’s true. I live alone in what was supposed to be a downgrade from the previous house, but it’s still huge and the basement is absolutely packed with stuff, not to mention all the stuff throughout the two floors of the main house.
And, in parallel with that, while out shopping today I was increasingly aware of my diminished mobility. Moving is going to be a nightmare. In fact, just preparing the house for sale is going to be a nightmare. And a further nightmare is finding a decent rental to move to, because they’re in short supply.
What am I doing about all this? I wish I had something useful to say in response to the OP’s question, but my special superpower is procrastination, and in this situation I’m applying its full force.
When I moved out of the previous house, I got a large dumpster delivered and by the time they came to haul it away, it was absolutely full, including with many heavy objects that I absolutely could not carry today. It’s all very depressing.
The only practical things I’ve done that are absolutely essential is arrange for lawn mowing during the summer and snowplowing in winter, plus my famous Ukrainian handmen when I need something fixed. I mean, I can still do some things myself, but if a ladder is involved, fuggetaboutit!