disk sector recovery

I've seen other posts on the same theme. I have TWO usb drives, 1 tera and 500 gb, with NON vital info. Non vital but it took me lot of time to gather the info, so, if possible, I would like to keep it.....
Now I understand that bad sectors 'Won't' be repaired, but 'marked' as bad, so the drive will not use them again..... so Checkdisk does the job, only it takes forever..... but also, wouldn't be advisable to retrieve the info BEFORE?
If YES, I don't know which program to use.
Can you correct me and guide me?
Thank you.

 

Have a read through the following link:
DjLizard's data recovery guide

The method outlined in the article would be my preferred choice of recovering your data. I have used it and found it to work extremely well.