I have an older money tree that is looking reasonably healthy up top, but has very long and bare stems. I attached a picture, but for scale, the green part starts about 2 feet from the soil.
Over time the green stalks have dropped a lot of leaves. How far back can I cut the green stems to create fullness without killing the plant?

There is no limit insofar as how far you can cut the plant back; but the enthusiasm with which the plant can respond to the chop depends heavily on timing (WHEN you cut it back) and the plant's level of vitality (health). The ideal situation would include you moving the plant outdoors as soon as nights are reliably above 55*, or move it in and out as temps allow, and timing of the pruning so it occurs a week or two before the summer solstice, 21 June. The outdoor vacation in open or dappled shade should do wonders for the plant, while lengthening days and increasing light intensity significantly increase the amount of food (a plant's true food is the sugar [glucose] it makes during photosynthesis) the plant can store as well as the plant's current ability to create food. So the combination of a healthy plant with a good store of reserve energy and the current ability to make food/energy at peak levels is as good as it gets.

The plant wants much more light than it's getting. How do you determine when it's time to water? Does the pot have a drain hole?

Al