How does someone prevent bundle branch block?

Difficult. Most bundle branch is a result of the aging process and aging in the conducation system. This not preventable. However, some bbb is result of aquired disease states including coronary disease. So a healthy life-style, blood pressure, cholesterol, sugar control, diet and excercise are good ways to start.
Simple! Just never have a heart attack or get old. These are the two most common causes of development of bundle branch block that you didn't have when you were younger. The wiring ages just like every other part of the body, which is why we're fortunate enough to have 3 bundles to get the job done. If one goes out, you're usually just fine.