Sources of testing show you really need to buy a case
Drop tests being conducted here on the Galaxy S3, while completely unscientific in nature, do provide valuable information. Some had thought that the addition of the Gorilla Glass 2 screens would have protected the phone from damage when being dropped. While that is an unrealistic expectation, you can see from the videos from Android Authority and Square Trade that dropping any phone onto concrete is going to cause a fair amount of damage. And it is precisely because of that you should look into a case for the Galaxy S3 which will be able to protect your investment. We all drop our phones at one time or another and the videos are a reminder of what can happen. After you watch the videos, you will reconsider whether you need a case for your smart phone.
Here we have a drop test conducted by Square Trade.
We also have a drop test done by Android Authority.
So, if the drop test on concrete is not enough for you, we have a water drop test which shows that the phone can handle being put into a sink of water.