I recently bought a small rubber tree to keep in my office. Currently, it sits near a west-facing window. I usually draw the blinds so that it receives only indirect light, but it occasionally receives some direct sunlight in the afternoon as well. So far, I have been watering it once a week, and allowing the soil to drain well after watering.

When I first got the plant, I would mist the leaves once a day, but I stopped doing that because after a week or so I noticed brown spots on a few of the leaves. Interestingly, only a third of the plant's leaves have any spots (and these leaves are in close proximity). For those that do have spots, it's clear that the spots are slowly growing.

Note: The bottom leaf also has some addition damage (tear) that is unrelated.