I get the itch, but here is the situation:
The ZHP sits at my parents garage in San Francisco. I live across the bay bridge in Richmond. It's only 14 miles, but it can take 45minutes up to well over an hour to reach my parents. Whenever I do visit my parents, it's usually on weekdays. The amount of time to take the car out, and then have to return the car back to my parents garage is a large pain in the ass. I guess that's what you get for free storage. :)
Someday I'll have a 2-car garage where my gf's E90 and my E46 will be able to sit so it will be far easier to take it out for a spin.
For now, quarterly drives makes sense.