Silicon lubricant (not WD-40) is what I use for the following points;

- Main mast where the radius block and swashplate make contact.
- Tail rotor shaft where the tail pitch slider ring make contact.

Lithium grease is what I use for the following points;

- Thrust bearings in the main blade grips
- Dampers in the yoke or headblock.
- Thrust bearings in the tail blade holders.

I lube the mast and tail shaft regularly, the thrust bearings and dampers (basically stuff that requires dissassembly) gets checked every 3 months (unless in a crash which makes it sooner).