Habits...

"It is possible that a man could live twice as long if he didn't spend the first half of his life acquiring habits that shorten the other half."

"The worst boss anyone can have is a bad habit."

"Good habits are formed; bad habits we usually fall into."

"One can conquer a bad habit easier today than tomorrow."

"It's easier to form good habits than reform bad ones."

Source: 14,000 Quips and Quotes for Writers and Speakers, by E.C. McKenzie