Use them (duplicate and "un-needed files" apps) if you want, just don't complain when they remove stuff you need.
How many duplicates do you think you have, anyway?
The only ones I have are actually aliases!
I don't trust any developer to tell me which files I have that are not needed, thank you very much!
If you are concerned about available drive space, that's a distinctly different problem. I'd suggest some of the numerous graphical disk usage apps and concentrate on the larger sections.
<Grand Perspective 4.5 MacUpdate stars>
<Disk Inventory X 4 MacUpdate stars>
<DiskWave 4 MacUpdate stars> note that it is only a 0.4 version
<DaisyDisk $10>
Admittedly from a biased source, you still might 'enjoy' the read: <
Why we don't believe in "clean your system in one click" tools: there's no magic bullet.>
Later: I downloaded DaisyDisk just to see what it does. And I realized I had lots of stuff in the iTunes Library that I didn't need! The app indicated I had an "Unknown" Album of about 5.5 GBs!
They were easy to find as they were files with identical names; "Offertory," "Message," "Postlude," etc. Sort by name. press Delete key, done. Thanks to your enquiry, I just removed over 4GBs!
