When Did They Stop Using Clones as Stormtroopers?

The Empire Stopped Using Clone Troopers After Order 66

In theory, the Clone Army should have been perfect for Palpatine's purposes. He had successfully established the Empire, but he was well aware there would be resistance.

When did they switch from clones to stormtroopers?

From clone troopers to stormtroopers

The term "stormtrooper" was officially adopted by all clone troopers in 19 BBY following Emperor Palpatine's reorganization of the Old Republic into the first Galactic Empire.

Why did they switch from clones to stormtroopers?

The main motivation for the switch to Stormtroopers was simply that cloning became too expensive. The cost of ordering, growing, and training clones was exorbitant, and the timetable for them to become full soldiers was lengthy.