The following paragraph is quoted from the linked article:
The downside of SSDs with the NAND Flash based chips is that they have a limited life span by default. While normal HDDs can – in theory – last forever (in reality about 1o years max.), an SSD lifespan has a built-in “time of death.” To keep it simple: An electric effect results in the fact that data can only be written on a storage cell inside the chips between approximately 3,000 and 100,000 times during its lifetime. After that, the cells “forget” new data. Because of this fact – and to prevent certain cells from getting used all the time while others aren’t – manufacturers use wear-leveling algorithms to distribute data evenly over all cells by the controller. As with HDDs the user can check the current SSD status by using the S.M.A.R.T. analysis tool, which shows the remaining life span of a SSD.