I was always in favor of brake dust shields, but never purchased a set. So I just methodically wipe down the wheels on all of the vehicles at night. Takes about 30 minutes, or usually less, since only one car is ever out at any time...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car