Psychology of habits

Why is habit considered a part of the academic field called psychology?

Studies about habit formation fall under the rubric "classical conditioning," I guess. The term refers to simple and beautiful experiments done by Pavlov in the 19th century. In over 100 years that followed academic psychologists successfully managed to obscure the original experiments with layers of complex terminology. They invented so many "new" labels that they had to classify the original research as "classical."

Can we simplify -or better yet- ignore this academic stuff to understand how habits are formed?

Yes. Personal development field is the non-academic version of the study of habits and how they influence human behavior.

And personal development formulation of habit comes with practical applications and solutions to specific problems faced by the individual.

Surprisingly, during our early education personal development is not emphasized; instead education aims to turn the natural human being into a dedicated consumer infected with various addictions to consumer products.

From reading the Wikipedia article it seems that stimulus and association are at the root of habit forming.