Pattern libraries
Over time, though, tiny fissures begin to add up to more serious cracks in the user experience. Your app may start to feel unpolished, asymmetrical. The process of creating pattern library can help your team focus on identifying and fixing these inconsistencies before they get out of hand.
An important development rule: Don’t Repeat Yourself. This keeps the code clean, and free of redundancies. Pattern libraries can help product teams follow this principle as well.
When to start with pattern libraries? Not too early in your project. This could be slowing down your process.
Cause at the beginning of a project it’s beneficial to be a little messy.