I recently purchased a floor jack and a jack stand set and would like to know about their proper usage. I noticed some people use rubber pads for their floor jack and jack stand contact areas - some of them are bought, some make them from hockey pucks, some use wooden blocks (I think I've heard of simply using a towel instead of rubber as well). I assume this is done to prevent damage to the underside of the vehicle or prevent slippage. However other people seem to not use anything and just jack the car up metal to metal and place it on bare jack stands. So which one is the way to go, are pads worth purchasing/making?