There are many good reasons for why you should use design patterns. One of the best ways to use design patterns is by determining the most common features on your website that have patterns in how they are used. And this article will help you understand how and when to use design patterns effectively.
Read the full article: Why Use Design Patterns
For a split second there, I thought you meant “Software design patterns”. It seems like there are a quite a few design terms out there, confusing the average developer (Think about “Breakpoints” for example). Although, I suppose a designer would see the same picture from the other side.
@Alexander: I lol’d when I read this, as I did the exact same thing the first time I heard about design patterns for web designers. I spent a few minutes trying to figure out how you could set up breakpoints, and then realized it was something different.