What is the risk of infection from using ear cartilage for Revision Rhinoplasty?

Using your own ear cartilage for a nose job is fairly common and
relatively risk-free. However, if you are experiencing the symptoms of
infection, it is important that you consult your surgeon(s) immediately
to track the root of the problem. In some cases, either the sutures that
bind together your new nose or the cartilage graft may become infected
post-operation. To prevent further infection and to address your current
situation, your surgeon may suggest the removal and re-application of
the sutures. Nevertheless, fearing infection should not stop you from
undergoing a nose job that poses other potential benefits. Those
present, the risk of infection should not be great enough to deter you
from a rhinoplasty procedure.

Cartilage grafts are amazingly resistant to infection in a proper rhinoplasty. While not impossible, it would be DISTINCTLY uncommon and should NOT be a lifetime risk as it regains a normal blood supply fairly quickly.

The risk of infection with cartilage grafting is extremely remote. It is irrelevant whether  the cartilage graft is harvested from the ear or inside the nose. On the rare chance that there is an infection, it would usually present itself in the first week after the procedure.