Where I live, if you visit certain restaurants you're better off using a valet. For instance, I went to the capital grill in Boston with my wife. I can spend literally 40 minutes looking for street parking, and then having to walk 20 minutes back to the restaurant, or I can give the keys to a valet and let him park it.
Seems like a no brainer to me.
Ahh The Capital Grille- great restaurant. I haven't been to the one in Back Bay in about a year. There is another one in Brookline/Chesnut Hill that I haven't been to but I hear it's not as good. I was at the Chart House last month where they valet park. We forgot to give the valet the smart key to the car so 10 minutes after sitting down on the 3rd floor the valet awkwardly showed up at the dinner table asking for it.
Valet parking isn't uncommon for hotels, restaurants, large medical offices, and hospitals in cities such as Boston since parking is scarce and the garages are usually down the street. Even outside of the big cities, there are a restaurants that just have limited parking. I know a few places that aren't that expensive that have valet parking just because it would be a nightmare for the customers.
I don't usually mind valet parking and I've never had an issue with damage. In some cases, I trust valets to park the cars more than the general public who may not be used to small parking spaces in parking garages. The country club my parents belong to also has valet parking that find ridiculous because the lot is right next to the building. Then I feel obligated to tip for something I could have easily done myself.
A few years ago when I was in college I had a couple friends who valet parked for the Taj Boston Hotel on the weekends. They told me in general the people who drove average cars- Toyotas, Hondas, etc tipped far better than the people with expensive cars- Austin Martins, Bentleys, Maserattis, etc. Apparently, the many of the super luxury car drivers wouldn't tip at all.
I usually tip $3-5 upon pickup depending on the location. If I'm parking overnight I may consider tipping on drop off as well because I assume it won't be the same guy working the next morning.