If you're looking for an environment that is best for people and plants alike then you should be looking at a humidity level around 40 - 50%. Of course if you like things humid you might want to go higher than this or on the other hand maybe you'd rather your home be a bit drier. But for maximum comfort and skin benefits we would recommend your humidity levels to stay around 50%. You can use a hygrometer to monitor your humidity and adjust it accordingly.