A few types of grease will conduct electricity and some will not. Good idea to know which is which.
DeOxIt is NOT a lube (neither is WD40 by the way).
Do some research before you use different products so you can avoid damage. Some o-rings and seals can be damaged by certain lubes.
Different lubes/greases can attract dust and grit (that is a bad thing to have happen).
Some lubes/greases can harden or become sticky after time (also not good).
Some lubes will change color after use (due to their composition or galling of the metal on the light, or both) and the change of color might mean nothing or it could be a warning sign.
You do not have to lube, grease, or perform other preventive maintenance every day, but (depending on how much you use your lights and how important the usage is) once every few months is a really good idea.
For most lubes/greases, a very little goes a very, very long way. However, if you put lube/grease on a dirty surface (even slightly dirty) it completely defeats the purpose. Learn how to properly clean and maintain your lights.
Knowing what you are doing and using takes a little time but will make sure that the light won't fail when you grab it and your rear end is depending on it. Do some research, look for MSDS's on the product, and do not believe all of the hype you will hear about some products.
And no, you do not need to spend a ton of money to get the right stuff for your needs and it will only take a few minutes to do some PM on your lights over the course of an entire year, and that's if you are doing it the right way.
This stuff applies to the D10 PD and virtually every light but different lights need different care since not all of the parts are made of the same material and not all of the lights use the same design.