I recently visited my health insurance provider’s website to pay my bill. In the course of five clicks, I was hit with four distinct interface designs, some of which looked like they were last touched in 1999. This inconsistent experience put the burden on me, the user, to figure out what went where and how to interpret disparate interface elements. By the time I got to the payment form, I felt like I couldn’t trust the company to successfully and securely process my payment. Style guides help iron out these inconsistencies by encouraging reuse of interface elements. Designers and developers can refer back to existing patterns to ensure the work they’re producing is consistent with what’s already been established.