SSD have a limited amount of write cycles. Therefore, there are two major factors in when and how an SSD dies.
1) If a lot of data are stored on it, then very little space is left being use for page faulting and everything else thrown at it, which will wear out quicker the empty flash areas, eventually leading to failure (Biggest problem now seen with Apple's SSD nowadays, where people have huge Photos and Music libraries on the local drive, making them slow and wearing out quicker than anticipated).
2) The type of environment/application the SSD is used in (SSDs with poor quality chips and low over-provisioning, on a server, will die quickly, while on mom's or granddad's laptop surfing Facebook a few times a week, will last forever - since many folks here do a lot of residential and people are more on their smartphone than computers, then their SSD will take a while to fail).
Poor quality SSDs die from cheap electronic components, like the older Crucial models. Other die from poor firmware bugs like the older Intel models (those also had a power-related bug, which all manufacturers learned from) and just about all SandForce controller based older models.
Would recommend staying away from consumer line of SSDs by LiteOn, Adata and Kingston.