One of the most important fact that a website relies on is consistency. Consistency can be achieved through a variety of methods such as good use of tabs and font.

The Layout of a website should be consistent to show the overall outlook. The layout refers to the basic framework and structure. A consistent layout will mean that visitor will spend less time navigating your website and more time engaging in the content. A consistent design also has a time/cost benefit as it means the website developer only needs to use a small number of reusable templates. A consistent colour scheme should also be implemented to reinforce brand identity.

Reference: https://cristianweierick.wordpress.com/2013/10/30/5-essential-core-principles-of-interactive-design-2/