The Chinese Banyan (Ficus Microcarpa) is a great indoor plant and will do well in any well-lit area in the house. Keeping high moisture levels will even make this Bonsai more forgiving. Although it does not lose its leaves, growth does slow down in the winter and as such required much less watering, maybe every 10-14 days. In the summer months, the best way to ensure your Tree is staying healthy is to feel the soil or stick a wooden chopstick in the soil. After 5 minutes pull the chopstick out and if it is damp, the soil is fine. If it is dry the Bonsai will need watering.
Repotting is suggested every year and the ficus can withstand root pruning happily. If a thick growing trunk is desired, the Ficus can be left in a large pot with good drainage and not be pruned back until the desired thickness is achieved. After which the tree can be pruned back and will continue its growth.
This Bonsai is probably your best bet as an indoor Bonsai and you will enjoy it for years to come.