Incremental. Many of the customs and rules were crafted in such a way to reinforce faith via repetition and penetration.

There's best practices for everything, including how to tie your shoes, put on a shirt, clip your nails, etc. Intermarriage and fraternization with people outside the faith are highly discouraged. This is to ensure Jews survive as a people.

When Jews stop being religious, the chances of them marrying Jews and having Jewish children drops significantly.

Ultra orthodox Jews marry ultra orthodox Jews and have ultra orthodox babies. By contrast, it's difficult to find a fourth generation reform Jewish family.

When I became lax in completing the 3 daily prayer rites per day, I began to lose my faith over time.