Just change the rear on my 2012 with 12,000 miles. I practice a lot of rear braking (Ride Like A Pro). The front are in great shape. Depends on the type of riding that you do. I have the service plan so I have to use OEM. When that expires I'll be installing Lyndall all around.

 

I just changed my rear brake pads along with the rear tire at 16000 miles. fronts are ok hopefully until the front tire needs to be changed.

 

I replaced mine just because I wanted to @ 31000 miles with a lot of wear left before getting to the wear indicators.
I think most of this is based on your riding style and even more on how much weight you carry.
I don't do stop and go traffic and only weigh 175lbs.
I see many of you with over 500lbs riding two up, you won't be getting the mileage I can get.
I installed the lyndal gold + and they are great, way better than the MOCO brakes