Confucy welcome back to the new old board.
Being a computer consultant I see way too much lost all the time to HD crashes.
The only way you know for sure if how you are backing up is working correctly is to restore to a different computer and see if everything is there and working.
If it isn't in two places then it either is lost or will be lost since there is only two types of hard drives, those that have failed or those that will fail.