Can taking the car to a car wash hurt the car's finish?

And if so, is it better to hand wash it about once a month, or just take it 
to the car wash anyway?

Are detailing places worth the money?  if i do a good, careful job on washing
and waxing, is a detail place going to be worth it?

reply to my email address: pfk1@crux1.cit.cornell.edu

pk4