I have no usual way on updating, but use about 5 ways in general...
Code:
portmaster -d category/port category/port
make checksum && make build && pkg_delete -f /var/db/pkg... && make install && yell
[some alias which does a big more or equivalent in sequence, checking
for changed dependencies from the last build]
and a few more. The shell script I run most often, I am suprised easily by
changes in dependencies.