I have seven wheelsets that I regularly maintain by dropping some oil on the spoke/nipple and the nipple/rim hole interfaces every three months or so. It helps with turning the spokes when you have to true the wheels, but I do it mostly because I live near the ocean. Kinda worried about some kind of sea water corrosion.

I use a mixture of one part Mobil 1 Synthetic 5W/20 Oil and three part Mineral Spirits for this purpose. It works very well.