(Just for the benefit of anyone interested and trying to search for it :))
Some days I actually sit on it for 8-10 hours (I hate to admit it).
I do take breaks and it can become fatiguing so occasionally, I feel like having a slouch so I go lie on the floor or use a regular chair (with decent posture) for a break.
Probably what this chair has done for me the most is make sitting with bad posture feel noticeably strange and unnatural.
There must also be something to be said for the fact that there is a “ramp up” time. I don’t think I have a stronger back from using this chair alone, although I guess I do have a less damaged and atrophied one. I do remember a time when it felt like certain muscles were getting stronger. I vaguely remember it taking a few months to become comfortable.
It’s worth mentioning that I do a fair bit of weight training too and that I’ve had the chair for about 8 years.
You can bounce aroundd on it which is fun too as the seat is mounted on a spring like a pogo stick.
Apparently this bouncing helps keep the joints lubricated.