When purchasing used desks, the structural integrity is paramount. You must verify the base material, prioritizing solid wood or high-grade steel frames over low-density particle board, which degrades quickly. Check the surface condition for deep scratches or delamination, and ensure that mechanical components like drawer slides and height-adjustment motors (for sit-stand desks) are tested for smooth operation. For B2B buyers, requesting a grading scale report (e.g., Grade A for 'like new', Grade B for 'minor cosmetic wear') is essential to manage quality expectations.