I have been having a lot of trouble with many of my plants lately, the past six months has proved to be quite challenging. I have no way of being able to pinpoint the problem, since there are so many factors involved: humidity is different, windows & sunlight are different, the heating of my house has changed (baseboard heaters now.....below each window, plants don't like that too much either), the windows are draftier.....etc. Add on the fact that I have let some of them go pretty dry, possibly too dry.

It could be root rot for all i know, but I am pretty confident that it isn't over watering, since i am a chronic underwaterer. Most of the plants that are dying or have died already, die the same way. Starting from the bottom and working its way down the stems, the leaves die and fall off. The stems go soft until the plant is pretty much dead. BUT.....in the end, the woody part of the plant becomes hollow inside, it doesn't seem to be rotting away. Root rot happens kind of like this, but it's also possible that it went too dry, and the roots are unable to nourish itself.
Luckily I have another hoya compacta, although this one was much nicer.
If anyone knows what is happening to my plants, please let me know......if you have advice, please share it........it's very discouraging watching my plants die.