Which condition signifies that an instrument requires lubrication?

The presence of joint stiffness in an instrument is a clear indicator that lubrication is necessary. Instrument joints are designed to move fluidly, and when stiffness is noted, it often means that lubrication or maintenance is needed to ensure the proper function and longevity of the instrument. Lubrication helps to minimize friction and wear, allowing the moving parts to articulate smoothly and preventing potential damage that could result from excessive strain on the mechanism.

Conditions such as tarnishing or rusting may suggest other issues, such as corrosion or improper cleaning, but they do not directly indicate the need for lubrication. Similarly, while an instrument that does not articulate smoothly can imply lubrication might be needed, the specific mention of stiffness directly relates to a malfunction of the joint that lubrication is intended to correct. Thus, identifying joint stiffness as the condition warrants attention for lubrication reflects a deeper understanding of instrument maintenance and care.