there is one separating detail that is not shared between most of us. It really depends on how long that tenant lives there. if they are living there for a long period of time and like the place, then yes you are a leech, but a good one since they enjoy living there enough to stay. On the other hand, if you switch tenants often because of high rent costs or bad housing(maintenance included), then you are just simply a leech and not a good one. If they leave for other reasons outside of your control, then you are not a leech and provided good housing for someone.

That is only for leeching aspects. I bet there are more complex thinking involved but this is what I think who a financial/real state leech is.