Is it worth running file overwriter (“shredder”) programs to securely delete existing data stored on my encrypted drive?
For most users, no – it would only have the effect of replacing encrypted files with encrypted garbage; neither is particularly useful to an attacker. However, if you have concerns of an attacker being able to gain your password (and other details required to decrypt your encrypted volume), it may still be wise to overwrite data before its deletion. This way, should an attacker be able to decrypt your volume(s), they will not be able to use data recovery tools to retrieve sensitive data.
