Dupes of photo is too tiny amount of memory to care about.
Dupes of video might be solved with more HDDs, especially if you are not Youtube and do not need to have petabytes of videos connected. Having enough of HDDs does not get rif of the problem per se, but makes it significantly less valuable.
If space is the main concern, I just sort files by size and lop off the videos, old application installers, iso's (!) etc.<p>cd {whatever}
du -ah | sort -n<p>"-)<p>It will show dupes, since they are the same size.