This tree was in the hall of our condo complex for months without any consistent attention (White Rock BC). The leaves were falling off in June and we thought it was dying and put it outside on our balcony. As you can see there is fresh foliage (much to our surprise) We don't know what it is and if we can leave it outside during winter. We're not always here during those months and thought to leave it in the hall again.
Maybe a Ficus benjamina. Not winter-hardy. Suggest finding a good spot indoors where it can live: these plants do not like changes in surroundings or light, temperature, or moisture levels. Will express displeasure by dropping leaves---as yours did. Daresay that this plant needs repotting.
Weeping fig sheds leaves when given a change in situation. It is better to leave it in the house and address whatever is bothering it in its permanent location than to move it in and out.
In general, repot when you would most other plants: when the pot seems too small for the size of the plant; if roots are protruding out the bottom of the pot (sometimes out the TOP); and when the soil is old, swampy, compacted, or provokes the reaction 'Yecch!' The latter is what I was thinking of, mostly. You say that the Ficus was neglected for months, and was clearly unhappy. The plant was untended, and so was the soil---the pot could have been used as an ashtray, litter box, or breeding ground for who-knows-what. Get it into some fresh, well-draining soil, give the roots, leaves, and branches a close inspection for any unwanted freeloaders, insect or fungal---and, as Ron and I stated above, pick a good spot for your plant, INDOORS, and leave it there. Bright yet not direct sunlight, no variations in light or temperature (don't situate it near a hot-air vent or doorway that will blast it with cold air in the winter, for examples), and water thoroughly and regularly, keeping it evenly moist. (Key word: EVENLY.) Also, choose a spot where the tree will have enough room to spread itself and grow.
