Applying polyurethane to wooden floors is a complex process that requires a high degree of skill and experience. Here are some of the key factors that an expert in this field would need to consider:

1. Surface Preparation: Proper surface preparation is critical for achieving a good result when applying polyurethane to wooden floors. This includes cleaning the surface thoroughly, removing any old coatings or stains, and sanding the surface to create a smooth and even texture. An expert would need to have a deep understanding of the specific tools and techniques required for this process, as well as a keen eye for detail to ensure that the surface is properly prepared for the polyurethane coating.
2. Choosing the Right Polyurethane: There are many different types of polyurethane coatings available, each with its own advantages and disadvantages. An expert would need to have a thorough understanding of the various formulations and their properties in order to select the best option for the specific application. Factors to consider might include the level of traffic on the floor, the desired level of sheen or gloss, and the potential impact of the coating on the environment.
3. Application Techniques: Applying polyurethane to wooden floors requires a high degree of skill and precision. An expert would need to have a deep understanding of the various application techniques, such as brushing, rolling, or spraying, and would need to select the appropriate technique for the specific application. They would also need to understand how to apply the coating evenly and without leaving bubbles or runs, as well as how to achieve a smooth and even finish.
4. Drying and Curing: Once the polyurethane coating has been applied, it is important to allow sufficient time for it to dry and cure. An expert would need to understand the specific drying and curing times required for the specific formulation of polyurethane, as well as how to create the right conditions for optimal drying and curing. This might include controlling the temperature and humidity levels in the room, or taking other measures to ensure that the coating dries and cures evenly and without defects.

Overall, applying polyurethane to wooden floors requires a high degree of skill and experience. An expert in this field would need to have a deep understanding of the various factors that can impact the success of the project, from surface preparation to drying and curing. By leveraging their knowledge and experience, they can achieve a high-quality and durable finish that will protect the wooden floor for years to come.