When do binaries get removed?

[Michael D. Norwick]

Good evening;

I am using;
$uname -r
$8.0-RELEASE
under Sun VirtualBox 3.1.6.

I am a long time Debian GNU/Linux user who has just installed the above 
release.  I have installed and used FreeBSD in years past but that was 
around the 5.x-RELEASE.  I have had a time installing applications from 
the ports tree (a story for another day) and finally resorted to 
installing binaries from the install dvd to get the full working X 
distribution.  I wanted to start with the 'minimal' set of packages and 
build from there.  At the moment I have the distributed binaries 
installed and am compiling/installing gcc 4.4 and friends.
I have the current FreeBSD handbook but it does not seem to have the 
answer to the following question.
When building and installing an application from ports, how does the 
original binary or script, in /usr/bin, /usr/lib, /usr/etc..., from the 
distribution, get removed?  The make install foo command does not appear 
to symlink the original application location to the new one in 
/usr/local/whatever.  Does it even matter?

Thank You,
Michael D. Norwick