If your garage door windows need replacement, consider using Plexiglas instead of standard glass panes. For one, Plexiglass is more durable than standard glass, and you need windows that will not break easily when they are accidentally hit by hard objects, while you are busy with a DIY project. Its "shatter-proof" quality makes it an ideal glass for a busy area, such as your garage. Also, Plexiglas is easier to cut and install. Although it is more expensive than standard glass, it is cheaper in the long run.