What is the primary reason for applying a base coat before nail polish?

Applying a base coat before nail polish serves several important functions, with one of the primary reasons being the protection of the nails from staining. Many nail polishes, particularly those that are darker in color or contain certain pigments, can cause discoloration on the natural nails if applied directly. A base coat acts as a barrier between the nail and the polish, reducing the risk of staining and helping to maintain the natural appearance of the nails.

In addition to stain prevention, a base coat can improve the adherence of the polish, ensuring a more even application and potentially extending the wear time of the manicure. However, the fundamental protective function emphasizes the importance of using a base coat as a key step in the nail care routine.