According to video stills posted on Phandroid and Techno Buffalo, it is very easy to take apart and repair the Samsung Galaxy S 4. According to the guy who sent the video, Mr. Nails, it is indeed one of the simplest smartphones to fix and that its smaller components are quite common. However, he also mentioned that the display is a bit harder to replace than other devices from the Korean company.
Also, comments and discussion ensue on the cost of components and repair, which will really depend on the availability of Galaxy S 4 parts and the technical know-how of the person repairing the item. Many agree that if a repair man finds it easy to fix the S 4, chances are that the cost of repair will be lower.
The S 4 small parts are thankfully quite easy to fix and anyone who prefers fixing things on their own will not find it difficult to do so in case anything happens to their S 4. Otherwise, some of the carriers offer insurance and it is highly recommended to avail of this for a fraction of the cost of having some parts of your S 4 replaced.