"Unfortunately, there seems to be a growing number of instructors that
lack personal experience in what they are offering to teach. It is all too
common for instructors to claim dozens or hundreds of dives as proof
of experience. However, these dives (if true) are often teaching dives and
not personally demanding. In choosing an instructor, be sure that the
instructor does the kind of diving for which one is considering training,
and that s/he does so on his/her own time; doing so will give one access
to a great deal of useful information. Before deciding, ask the instructor
for a resume, and ask those locally what their experience has been with
the prospective educator. Individuals can often get a sense of an instructor
by personally discussing course content and structure."
Source : GUE - The Fundamentals of Better Diving.