It is 3+ years old and feeling a bit klunky, so I greased the plastic friction ring at the bottom of the stick with some light bicycle grease (NOT OIL!). What a difference. Action is so smooth. Feels better than new.
I made sure not to get any down inside the base, though I'm sure some will find its way in over time. Shouldn't hurt anything, but hey, if so, it is due for replacement anyway with as much use as it gets.