In my practice, I use septal cartilage in about 90% of the time, ear cartilage about 30% of the time and rib cartilage about 30% of the time. The decision of which source to use (and sometimes I will need to take from more than one site) depends on a few things:
1. How much overall material I will need. As a surgeon who uses a structural philosophy, I tend to need more material in order to keep the nose strong while aesthetically balanced. Rib provides the most material, but does involve more time and recovery. Septal cartilage is usually the best first choice, unless a large augmentation is needed (for example to raise the bridge a lot).
2. The type of material needed. For example, ear cartilage is curved and springy. This does not work well when you need strong or straight cartilage grafts. But this type of cartilage is ideally suited to provide curved support for certain areas of the nose like the outer wall.
3. The availability of cartilage in any given site. This is important especially during revision rhinoplasty. When previous surgery has been performed, there may not be graft material available in the septum or even the ear.