As I've mentioned in the past, I am a firm believer in Steve Martin's advice from My Blue Heaven, in that "you tip everybody," but as I was bringing my car back this afternoon, I had a thought.
Valet parking... do you tip the guy who takes your car (to make sure to keep it safe), the guy who brings it to you (for being quick at getting it to you)? Both? Neither? Just seems like the tips alone could add up after a week of in-and-out valet service. Of course, there's no option for non-valet parking, so I can't make it easy on myself that way.
At least tipping.org suggests only a buck ... I guess $2.00 a trip out and back isn't bad in the grand scale of things.
Barnaby's Rule of Valet Parking
If you care about your car at all, and especially if you care enough to worry about how much to tip, don't ever let it be valet parked...
Usually I tip when I collect my car.