What does this quote mean?

“Sweet are the uses of adversity.”

Adversity is presented as capable of yielding insight or value even when the experience itself is unwelcome.

Source note: As You Like It, Act 2, Scene 1; Duke Senior reflects on what adversity can reveal while living in exile.

“You can turn over a new leaf every hour if you choose.”

A failed plan need not govern the remainder of the day; Bennett frames each hour as another practical opportunity to restart deliberate action.

Source note: How to Live on 24 Hours a Day, discussion of beginning a programme of self-directed use of spare time. The sentence is practical encouragement within Bennett’s period self-improvement argument.

“Generally then if you would make anything a habit, do it.”

Repeated behavior trains the corresponding habit, so change depends on practicing the desired action rather than merely endorsing it in theory.

Source note: Discourses, George Long translation; Epictetus explains that faculties and habits are strengthened by corresponding actions.

“Not a day passes without its discipline, whether for good or for evil.”

Daily experience is always training something, so ordinary choices can reinforce either constructive habits or patterns that make later self-command harder.

Source note: Character, Chapter I, “Influence of Character,” Project Gutenberg #2541. Smiles introduces the sentence while explaining that character is formed by many minute circumstances under partial individual control, so each day contributes discipline for good or ill.

“It is reflection which forms habits, and fixes principles indelibly on the heart.”

Habit formation becomes stronger when action is joined with reflection, because principles understood and revisited are more likely to guide later choices.

Source note: Thoughts on the Education of Daughters; Wollstonecraft connects reflection with the formation of durable principles and habits.

“It is not a lost year, but one that may prove the most helpful of any you ever know.”

A painful or disappointing period can still become useful experience when it changes judgment, humility, resolve, and the way a person begins again.

Source note: Jo's Boys; the reassurance follows a setback and reframes a difficult year as experience that may later prove unusually helpful rather than simply wasted time.