You might need to rethink your clustered index

A common table design that you might be familiar with, is to have an identity column, could be int, or long, or uniqueidentifier, and then, a clustered index is conveniently created on that column. An identity is, technically speaking, the perfect choice for clustered index - it is not null, it is unique, and in most case it’s small. But is that really the best choice?