It is easy to see on the picture to the right that Wenger made a quality SAK! When they are as nice as this there is little need for maintenance I would say. It is the Major model you see.
Having tweezers, toothpick and some oil is smart to have extra even so.
There is not a spot
on this SAK which is from about 1994. To make a sandvich construction like this requires a production with superior tolerances and quality control.