Babies typically start crawling around 6 to 10 months of age, but on average, many babies begin to crawl around 8 months. Therefore, Dwight and his wife should aim to baby-proof their home within that time frame. Based on the provided options, they would have approximately six to eight months before they need to fully baby-proof their home, with the most common time being around six to eight months.
So, the best answer from the choices given would be: six months or eight months.