I've been thinking if I'm going to defrag my 2tb and 3tb external hard drive (WD green cavier).. . I've only use this two external hdd to save lot of my anime collection,movies, and other files like mp3, doc etc...

1. what benefit is there to defrag my externals?
2. If I'm going to defrag my externals does it affects my anime collection videos (what I mean does doing this makes any bad effects to any of my anime video collections?)
3. when should I defrag my externals?

what I really care is my anime collections not much of the movies
^___^

recently when I'm storing movies I've downloaded to my externals my 2tb 2nd partition suddenly become not responding and I waited it and nothing works so I turn off the switch button of my external 2tb, then I switch it on again the 2nd partition pops up the a message box with two options scan and continue, so I choose scan it result said that some of my files(actually the movies folder I've been storing on the externals) have been move to "found folder" but I don't how to find it... with this incident I'm worried that someday it will happen again... my anime collection is in 1st partition thank goodness..

I need advice with experience please... not just pretty talks to earn points here..

You are aware that both partitions are on the same physical hard drive... which if it fails... EVERYTHING will be gone?

Do you have utilities that will tell you if you have bad sectors occurring in ever increasing numbers?

What you are describing isn't the result of something needing defragmented... even though it could probibly use it... but more of an indication of bad sectors where the allocation tables are stored.