There are three types of users: beginners, intermediaries and experts.

In reality most users are neither beginners nor experts, they are intermediaries.

For a user to go from an apprentice to an intermediate, he does not need to invest a great deal of time. Considering that improving is something rewarding, few users remain in this learning phase; either they like it and go on to intermediary or they give up and look for other alternatives.

As in all cases, there are specific situations, and when developing specialized products, it is best to develop the product with an expert type of user in mind. Specialist users usually have very technical knowledge and need tools that allow them to perform tasks with great proficiency. In the same way, there are certain types of products that have to be developed with apprentices in mind, such as public kiosks or even for disabled people.

In the practical world, engineers have a tendency to develop interactions for experts, while marketers people have a tendency to develop interactions for learners, but the conclusion that the authors of About Face 3: The Essentials of Interaction Design have reached , was that the most important group is the intermediaries.

“Programmers create interactions suitable only for experts, while the marketers demand interactions suitable only for beginners, but – as we have seen – the largest, most stable, and most important group of users is the intermediate group.”
Cooper & Reimann & Cronin

The main objective is to fluently and quickly turn the beginners into intermediates and avoid as much as difficulties that do not allow them to proceed to experts. Keeping the users in a temporary state where their necessary skills are average.

Beginners

A new user initially has to easily understand the concepts of the product, otherwise he looks for new alternatives.

In order to be intermediate users they need extra help from the program, but once they are, this extra help is no longer needed, even having to disappear, otherwise it will harm them (intermediaries) as they already know the concepts.

They have a tendency to learn to perform actions through menus. According to the authors of About Face 3, a good way to look at these types of users is to think of them as very intelligent but very busy people, who don't want to know anything about the process, they just want their action done.

Intermediaries

These types of users already understand the basic concepts and are motivated to learn and discover more, if they don't have to learn a lot at the same time.

They already know the features they use regularly and the ones they rarely use, so they expect those tools to be well positioned and accessible in the interface; where they can easily be used and remembered.

They are usually aware of the existence of advanced tools, although they do not need / or have the knowledge to use them. However, this knowledge is important if they want to become expert users.

Experts

Specialists are characterized by having a very fast and established workflow.

They regularly use shortcuts and expect every feature they use to have a corresponding shortcut. As they possibly work with the product several times on a daily basis, they quickly absorbed the standards and concepts of the interface.

They are constantly looking to learn more and understand the behavior of the program. They expect powerful new tools, and their experience with the program makes them respond well to new complex tools.

“Yes, you must provide those features for expert users. Yes, you must provide support for beginners. But in most cases, you must apply the bulk of your talents, time, and resources to designing the best interaction possible for your most representative users: the perpetual intermediates.”
Cooper & Reimann & Cronin