Assume a hab in outer space with 1 atmosphere pressure and 23ºC (comfortable room temperature),
To simulate gravity, the hab is spun. Acceleration is $\omega^2r$ where $\omega$ is angular velocity in radians/time and r is radius of hab.
Obviously the lower the "gravity", the smaller the hab can be. High rpm's make people sick and less gravity reduces the need for high rpm's. Also the structure doesn't need to be as strong.
I am wondering at what point gravity overcomes surface tension and water flows downhill. Thus the astronauts could enjoy showers, flush toilets, and their sinuses could drain.