Do you use RAID for your Mac hard drive or external drives?

I always hear some geek guys online talking about RAID format of their hard drives.

The only thing I know about it is raid 0 is very fast in writing and reading files. but not safe, as all your data will be lost if the drive crashes.

Raid 1 is safer as there is one mirror drive to backup... but not as fast as raid 0

Anyone uses raid?

I bought a WD 1T USB 3 harddrive last year, but I did not even format it to use. Does that matter?