Misconception #1: You should wait until the break on the windshield spreads before replacing it
Wrong. Driving with a broken windshield is dangerous. Windshield cracks can spread across your line of sight while you're driving, and decrease the structural integrity of your windshield. This will reduce its effectiveness at blocking debris, and protectiveness in the event of an accident.
Also, it's illegal to drive with a crack in your line of vision here in Missouri, and your vehicle will not pass a safety inspection. Waiting until it spreads, you may disqualify your chances of getting it repaired.