Each leaf symptom could have a different cause. If leaves are black, it's likely due to over-watering. Take the plant out of the pot and you'll probably find water in the bottom.
To minimise wet roots, I think it's best to have an inner pot as well as the outer one. However, when I do this, and still sometimes see black leaves. I empty the excess water from the outer pot, cut off the black leaves, and don't water again until the soil has dried out.
I'm not sure about the cause of the yellowing. Your photo also seems to show brown leaves, which I would guess could be due to a lack of water. Perhaps you've under-watered at some point?
I think the best approach is to get to know much water they need in your climate. Healthy leaves are probably a sign that you've got the balance right.