[dnanian]

A hard drive kind of wears out every time you do anything with it.

Just because a drive is already formatted doesn't mean you should just use it. Some manufacturers (WD comes to mind) ship drives with the same low-level IDs, which can mess things up. I always advise a simple format, which assigns a new ID, before using it.

Q2: See above. (If the drive is not properly partitioned you do have to repartition it. The FAQ explains.)