Explaining what you want to achieve with your research will help you to better structure your research.
If you do research in the application context your reason for research will probably be to obtain a product which is relevant for the stakeholders. You are trying to optimize the fit between your product and the application context. Oftentimes you want to assure that your product is up to contemporary quality standards. In those cases, you want to use all the expertise available to create your product. You do this by doing research in the "available work" domain. As there are few methods that simultaneously optimize fit with the application context and expertise based on available work, it is often necessary to combine both types of methods in the project.
Similarly, there is a tradeoff between optimizing overview and certainty. Often, mostly in the beginning, you want to gain a good overview of what is needed or what is available. At other times you want to test specific aspects of your work, to make sure it works. In these cases, you try to configure your research to optimize "certainty" about your hypotheses or goals.
Lastly, in most cases your research might require a data oriented approach to justify your choices, as this information is less dependent on who executes the research. Sometimes, however, it is a good idea to choose inspiration-based methods, in which you personally will have an affect on the answers that come up, such as the Brainstorm method. Data-oriented methods are very suitable for providing justification, while inspiration-oriented methods result in more creative, innovative solutions.
On the one hand, these trade-offs help you find suitable methods for obtaining the necessary information to achieve your goals. On the other hand, they also show you that to arrive at a good solution, you will need a combination of methods on the various axes: triangulation. This way you achieve both overview and certainty, a good fit as well as making use of existing expertise. Which aspects are most important in your situation will depend on the goal of your specific project. Don't forget to take into account the limited amount of time available to you!
P.S. You can also consciously decide to combine multiple methods within the same research strategy. Instead of using triangulation to achieve multiple trade-off considerations, you then choose to be more thorough in one aspect, making you more certain of your answers to the questions in that area. The most important thing is to make conscious decisions and to justify them based on the goal that you are trying to attain.