Like what many have already said, I think it's impossible to keep a daily driven, black car swirl free and if that's what you're trying to achieve you'll just drive yourself crazy. Heck, sometimes I even wonder what the point of washing my car is for when a few hours later it's dusty/dirty again.
At least when I wash my father in law's car, it stays looking nice for awhile since he has a sand/tan color paint job. Everyone else in our family have black cars unfortunately. Sometimes it feels like my main job is to keep the family's fleet of vehicles clean. It's almost becoming too much of a chore, especially when I already have enough on my hands to deal with.
