Buyers arrive with a mental model built from every other website they have used, and they expect yours to work the same way. That model includes assumptions about where navigation lives, how categories are grouped, and what clicking a label will produce. When the site matches those expectations, buyers navigate efficiently. When it does not, they make mistakes, get frustrated, and leave.
Mental models are shaped by individual background and cumulative web experience. Users who have visited hundreds of SaaS sites expect a top navigation bar, a resources section, a pricing page, and a demo CTA in predictable positions. Visitors use the site's structure to decide within seconds whether the company understands their needs and is worth contacting. The gap between how designers think about their own site and how buyers actually perceive it is one of the biggest usability risks. Card sorting and tree testing are two research methods that reveal how real users categorize concepts and navigate hierarchies, helping close that gap before a single page is built.