What do you want to achieve?
This question is in fact forcing you to define the testing itself but not from an academix point of view but with your own practical experience and judgement.
Naturally, your background will have a huge impact on your own way to approach the testing.
From an application development background,you will be convinced that you want to deliver an application free of bugs.
From a end-user point of view you will be tempted to consider a new functionality on smilar way that a kid is discovering the world,i.e by the try and error approach.
The advantages of the first approach is that it is providing a lot of data or indicators that can be used to give confidence in the so called quality of what you have produced. BUT, it leads to often in delivering a functionality that is not covering the original needs and which is therefore quickly useless, On top of that it gives a poor user experience to the end-user.
The second approach, as already explained, is closed to the natural way to discover something new and therefore to assess the adequacy of it with the needs. However, it gives little indicators to justify your opinions.
Therefore, the ideal is to find the balance between these two elements, but in this equation, you need to consider the reporting management expectations. The higher it will be the more structure needs to be your approach.
Having say so, my opinion is nowadays to empower the end-users and to trust there judgment. Indeed, at the end they will have to use the tool and in general they will avoid complicating there professional life with poor functionalities. This recommendation will also have additional benefit like reducing the testing cost and ease the acceptance of the new function by the full user community.