all the items you are using are considered digital storage, USB, HDD, CD, ... and they all have the same risk of "data loss over time" and also "hardware failure due to age or electrical shot, damage,..."
and as for renaming, it can be good if you are paranoid but just a simple encryption with what your wallet offers (usually it is AES encryption) with a strong password would be enough.
and the solution is that it is best if you keep a different type of backup, for example printing the private key or your seed on a piece of paper (which can also be encrypted PK or Seed)
in summary: wallet file on USB + backup on DVD + Printed paper all encrypted is more than enough.
Yeah i know about that... that isnt what i was asking...
My question was specifically on the topic if the renaming of the files, storing them in RAR file, and renaming even the rar file cant somehow damage the file...
For example if i rename the file to doc and by accident try to open it, it opens in word (or rather word programs loads but fails to load the document... wont the word document attempt to write something to the file (when he (badly) considers it as a word file)...?
Its not really likely i guess but you never know what can fuck up in IT... :-)...
So is it safe to do it this way?