CL - you hit the nail on the head in your first sentence !
It all depends on their ability...

I have only worked in middle/high schools and a (decent) TC. Sadly, there are many students that would struggle to define a 'sentence' let alone know how to build one correctly.

I believe that recognising a students' ability and then teaching them to that ability is one of the fundamentals of being an effective teacher.
However, the constant 'problem' in many schools is the fact that students in the same class often have vastly different levels of ability.
Creating lessons that the students with a lower-ability can understand, leaves the 'better ones' bored-to-death and vice-versa.