I have a treadmill, which I probably won't be using again, since my walking is down to a minimum, but my husband has started using it. I bought one that folds up, smart decision. I also have a weight machine in my bedroom, the electric kind, not the one with the heavy weights on it. My son and I were in a store when a kid smashed his hand screwing around one of those (yes, where was his mother? About 2 minutes after he did it, screaming she would sue, instead of calling 911. My son and I took charge. He was bleeding, and no one else would touch him. Sad, just sad.)
I can still use the weight machine for doing crunches without hurting my back, and I use it for hooking my traction devise to, lol...works well, even if not what they designed it for.
The most useful piece of equipment I have now is my cane, and my dear Dachshund Daisy who walks with me to keep me from wandering like a drunk, lol.