As above, 1,5 year old indoor plant in a pot. About 3 feet high. Some leaves turn yellow and then fall off, looks like they were cut off right at the stem. Too much water? Too little? I read somewhere that this can be normal, is that correct? The brown spots are unrelated, they turned up when I didn't water it sufficiently a long time ago. The top of the plant looks lush, big leaves and no spots or anything. http://i.imgur.com/rVraJ.jpg?1
Looks like normal leaf death to me. However, you might want to carefully check the plant for spider mites - you've got what looks a bit like mite damage on some of the leaves. Spider mites aren't the end of the world, and they're fairly easy to eradicate.