Hi Lostboy,
Thats a tough debate. Some will say yes and others say no. To get more attention and feed back in the forums start a new post and title it "lubricating gears/cogs & bearings".
I personally only lube my bearings, I'll take them out, place them in a corner of a plastic bag, fill it with a little lube, twist the bag, squish it around, then dry them with a paper towel. It washes all the dirt and buildup inside them.
From what I understand about the gears is that they are self lubericating, Plastic on metel parts do not need grease or oil. It will only junk up your gears and attract dirt.
I've heard of people lubing their motors and others yelling at them for that. Some have said to not lube anything at all.
Caution: Some lube's will expand plastic and soften it. Use something wiht 100% pure silicone or read the lable to make sure its safe.