In relation to the development of IT-products it is very important that the software supplier is aware not only of the target group but also the field of application. Usability should characterize the whole IT-design process as, in relation to this context, design includes more than merely those aspects which are visible to and thus can be interpreted by the naked eye. The study examines the specific qualities and properties that substantiate the usability and the demands that a customer rightfully expects from an IT-product. The user and the customer are highlighted in the same context in order to demonstrate that it is through the customer that an IT-product is defined as being useful. Thus, from this perspective, the user and customer can be considered as being the same person. The empirical survey was based on those factors that were considered to constitute usability and each interview was conducted using these usability factors together with the intended IT-product. The survey has been carried out using analysis models in order to enable the assertions to be both validated and tested and to ensure the appropriateness of the model’s system and also the independence of the method. This qualitative study has been carried out using randomly chosen respondents and IT-products and the perceptions of these respondents in relation to what they felt were the properties that represented a usable IT-product have been noted. The analysis section deals with the usability properties which have been assumed to further substantiate the five usability factors utilized in the survey.  It is apparent from the analysis that is it quite possible to determine a minimum level of what constitutes usability and that this can be applied regardless of what IT-product is being described. The conclusion to be drawn from this is that the opinions and experiences of both user and customer should be considered in order to provide guidance in relation to satisfying the requirements with regards to the design of IT-products.