I am a young 54 year old man and would like to know if there are any
free or  inexpensive vocational / aptitude tests available that are
more precise and less general than the usual Myers-Briggs et al.
I have a multitude of talents and interests- I consider myself a bit
of a Renaissance Man- and have always found the usual tests far too
simplistic, limiting, and facile in their conclusions.
I am looking to begin the second part of my working life and need help
to arbitrarily  narrow down my prodigious interests and energies into
the best direction for me.

Almost anything medical should be good if the economy sags. Otherwise
computer related looks good, perhaps computer for medical makes sence.
You don't want to learn to fix small appliences, as that has shrinking
oportunities, unless foreign manufactures decide the dollar is
worthless, compared to the yen and euro. The tests helped me land a
job, but I never took one that helped me choose a profession. Where do
you live? Likely there are good reasons why you should not relocate,
or stray into fields for which your present expertise would have
little value.   Neil