So I recently lost a small crassula to root rot.
My large crassula (about 2 foot) was doing fine, but I just found a branch that had gone very soft, and broke away easily.
I'm now worried this has root rot too, but I had been much more conservative with the watering of this one. The top inch (at least) of soil is completing dry, so I'm not sure if I've over-watered or under-watered it.
I really don't know if it needs a good dose of water, or the complete opposite. Any help?

Can you post some photos? Is it in a pot with drain holes? What is happening at the bottom of the pot? What light source do they have? Can you tell us where you live? Outside weather, climate and latitude do have an affect on indoor plants.