Customer research is the discovery half of UX research: the work you do to understand people before you have anything to test.

In practice it’s four main methods, and which one you use depends on what you need to see.

In-depth interviews: One-on-one conversations, usually an hour. The workhorse. Best for understanding motivations, decisions, and how someone thinks about a problem in their own words.

Contextual visits: We go to where people actually use the thing: a home, a shop floor, a clinic, a classroom. Probably the most data-rich sessions available, because you see the interruptions, workarounds and constraints nobody thinks to mention in an interview.

Diary studies: Participants record their own experience over days or weeks. Best when the behaviour is spread out over time, or happens somewhere we can’t be.

Focus groups: We’re usually sceptical, because people perform for each other. But with the right question, the right people and tight facilitation, they earn their place.

Most projects use one or two of these, not all four. The choice comes from what you’re trying to learn, not from what sounds most thorough.