Your website design is crucial because your clients look and expect so much from your design. As humans, we all have our senses appealed to the visuals, and we are naturally drawn to good website designs. Thus, when it comes to your website design, the users usually see your business as reflected on the website and the visuals it features.
If the time comes that you stumbled upon an old website design, it usually reflects badly on that company. Others may think that it is really old, and that others may doubt their company objectives, services and products. Humans are really biased on the businesses when it comes to the look of their websites.