1. The Blackjack Law refers to the formation of a habit through 21 days of repetition, and a stable habit will be formed after 90 days of repetition.

2. If an action is repeated for 21 days, it will become a habitual action. If the same idea is thought about repeatedly for 21 days or verified repeatedly for 21 days, it will become a habitual idea.

3. Generally, you need to remind yourself to make changes from the first to the seventh day of the process, and the process from the seventh to the 21st will become more natural.