This plant breaks more hearts than any other houseplant. Walk through the room and it drops its leaves. Move it and it drops its leaves. Look at it and it drops its leaves. It is a rather hysterical plant and shows its hysteria by dropping all its leaves every chance it gets.
Though there are many varieties of ficus, benjamina is the one most often found in homes and offices.
The most common reasons for leaf drop are improper watering ( too much or too little ), moving it or insects. It normally sheds its leaves during the dry season. So when your heat comes on for the winter it may drop its leaves in response.
It will recover from leaf drop growing new leaves quickly. I find the more humidity I give it the sooner it will leaf back out.
Keep an eye out for scale and spider mites, both like ficus and both will cause it to drop its leaves.
So if is so much trouble why bother? Because it is a stunning, impressive house plant when you can successfully grow it. It also makes an excellent bonsai plant.
Ficus seem happy in just about any light, but the more light you can give it the happier it will be.
Water carefully, they are prone to root rot. Check the pot weekly but only water when the top couple of inches feels dry. Remember the center bottom is where it will stay damp longest. Some people report it responds well to having a tablespoon of vinegar added to a gallon of water for watering.
Prune them into what ever shape pleases you. The trimmed sticks may be dipped in rooting hormone and planted in a new pot of soil to give you new plants. Keep the newly planted ones moist until you see new leaves, then water as usual.
Sap will leak from the cuts, be sure to keep it off carpets and furniture. The sap ( latex ) in ficus can cause allergic reactions.