What is the main purpose of sanding wood before applying a finish?

Sanding wood before applying a finish primarily serves to prepare the surface for adhesion. When the wood is sanded, it creates a smoother surface with finer pores, which allows the finish—whether it's paint, varnish, or stain—to bond more effectively. This improves the overall appearance and durability of the finish, helping it to adhere properly and preventing issues like peeling or bubbling over time.

Additional benefits of sanding include the removal of any rough spots that could interfere with even coverage of the finish. While options like removing previous finishes, adding texture, or changing the color can be aspects of working with wood, they are not the main focus when preparing a surface for a new finish. The principal goal is always to enhance the adhesion and quality of the final appearance.