Just did the fronts on my 300E a couple of weekends ago. Took 30 minutes.
Rears are even easier. I replaced all four the previous time, but just did the fronts this time.
Usually the fronts wear out about three times faster, but if you haven't done the brakes in a while, the rears may need attention too. You can do a visual inspection with the wheels off to determine.
You probably have at least 5K of meat left on those front pads before the yellow light stays on all of the time, and then rotor damage may result.
BTW rotors are cheap too, and should be replaced about every two to three brake pad replacement cycles.
Dealer might charge upwards of $250 to do the brakes on all four sides. But as posted earlier, it's a simply DIY and you can save a few hundred dollars if you get the parts here and spend an hour or so doing the brakes...plus you get the satisfaction of having done it yourself, as well as knowing exactly what condition your brake system is (as opposed to taking someone else's work for it)...
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