Ficus benjamina is a beautiful house plant.  It does need to be repotted every few years, some signs of this need are:  roots growing through the drainage hole or up through the top, new leaves are smaller than normal, and other signs of stress.  This article, How to Repot a Ficus Tree, gives you the steps.  Late winter or spring are the best times to repot, because the plant is starting to actively grow after its winter rest.   You'll have to decide if it's better to repot now and give the plant a fresh start or wait until growth starts in the spring.

For Ficus these conditions are optimal:  1.  light - indirect or filtered light, not direct strong light,  2.  temperature greater than 60 and better greater than 70 degrees,  3.  watering - moist soil, but not wet roots, so only water when the soil on top of the pot is dry.  You can increase humidity by placing the pot on a saucer with gravel or small rocks then add water - the rocks keep the pot above the water level, and 4.  fertilizer - decrease or even stop fertilizing in the winter, then increase to once or twice a month when growth starts in spring and they are growing fairly rapidly.  A slow-release fertilizer will give your plant a steady supply of nitrogen.   This article,  Ficus benjamina,  has good information on several aspects of Ficus care.