I have a droopy nose tip. Is it due to a too long septum or an excessive cartilage? (photos)

  The tip can be refined and elevated.  The caudal septum may need a bit of adjustment as well.  Kenneth Hughes, MDLos Angeles, CA

Rhinoplasty procedure can address the drooping tip by lifting  and narrowing the tip with suture techniques to the lower lateral cartilages. The dorsal hump can be shaved down and osteotomies will then be required to narrow the nasal bones. The caudal septum can also be trimmed back which is too long. For many examples, please see the link below to our rhinoplasty photo gallery

I assume by cartilage you mean the lower lateral cartilages of the nasal tip, since technically the septum is cartilage as well. The answer to your question is that it could be either or both, depending on what the nose feels like and looks like once you open it up during surgery. Sometimes you can get an idea preoperatively based on how firm it is, given that septal cartilage is more firm than tip cartilage usually. That said any competent surgeon would be able to correct the issue regardless of the cause.