Will my watch be more accurate after you service it?

Your watch will be as accurate as it should have been
from the factory.  There is no miracle oil or procedure
that we can do to increase accuracy that wasn't there in
the first place.  Also, let me say this; A mechanical
watch will
never, never keep 'absolutely perfect' time, it's
just in the geometry of the design.  After a Rolex (or
other Swiss watch) is serviced it will
never keep 'perfect'
time -- when it left the factory it never kept 'perfect'
time.  The standard for chronometer movement is
typically -2 sec/day to +3 sec/day (again, not perfect),
this is a total of 5 seconds per day. Typically the
chronometers we service are in the 10 to 40 seconds per
month category, again, much depends on the quality of
the watch.