When you least expect it, you will experience a clicking hard drive so before it happens, here are some things that you will need.
Stethoscopes
Sometimes the Click of Death will be noticeable but other times, it can be faint and when you have multiple drives in your noisy system operating or cloning on drive station a stethoscope can come in handy. I find the 3M Littmann Stethoscopes to perform well when held properly.