Sliders under everything and one time I made a resolution to never buy any furniture that wasn't on wheels, lol. I have an antique drop leaf table that's on wheels and a kitchen island on wheels. I wish I had more.
I've downsized and gotten rid of a whole lot of furniture including a hulking coffee table. Now I use a tiny cedar chest instead. But I worry about moving my bed or the heavy leather couch.
As for furniture to buy if your old stuff wears out, I remember a great aunt who came to visit one time and she loved my Boston rocker. I still have it and I guess it would be comfy if you needed support for your back instead of this squishy non-supportive furniture that so many of us have. I love furniture until I think about moving.