Habit

A review of Better Than Before: Mastering the Habits of Our Everyday Lives includes a number of quotations from Gretchen Rubin's book, among which:

Habits are the invisible architecture of daily life. We repeat about 40 percent of our behavior almost daily, so our habits shape our existence, and our future. If we change our habits, we change our lives. ....

Self-control is a crucial aspect of our lives. People with better self-control (or self-regulation, self-discipline, or willpower) are happier and healthier. They’re more altruistic; they have stronger relationships and more career success; they manage stress and conflict better; they live longer; they steer clear of bad habits. Self-control allows us to keep our commitments to ourselves. Yet one study suggests that when we try to use self-control to resist temptation, we succeed only about half the time, and indeed, in a large international survey, when people were asked to identify their failings, a top choice was lack of self-control. ....

And that’s why habits matter so much. With habits, we conserve our self-control. ....

Habits make change possible by freeing us from decision making and from using self-control. ....

When possible, the brain makes a behavior into a habit, which saves effort and therefore gives us more capacity to deal with complex, novel, or urgent matters. Habits mean we don’t strain ourselves to make decisions, weigh choices, dole out rewards, or prod ourselves to begin. Life becomes simpler, and many daily hassles vanish. .... [more]

Habit frees the mind from having to decide, allowing thought about other things.

Better than Before: A Psychological Field Guide to Harnessing the Transformative Power of Habit | Brain Pickings