There are many different reasons why people want external render done to their properties, there for so many types of rendering.
Some people want rendering on a new build property, some people wants because the existing render on their property has been damaged, cracked, de-bonded, they want simply replacement of the existing render. In most cases it would be a conventional Sand, Cement and Lime onsite mixed render. Due to its density, high cement content, it tends to crack, much more easily than ready mixed or non-cementitious renders.
Even the existing render you have at the moment on the façade of your property that you are looking in to replacing is sand and cement, you do not have to replace with sand and cement render. There are a lot of alternatives available now than ever before.