how long do original brakes last?

All of that having been said, it has been common knowledge that ever since they went away from asbestos brake pads (quietest ever made) the semi metallic chew metal off the rotor every time you stop. So when the brake pads need replacing the rotor is more than half gone and will not make it to the next brake pad change. So you can be proactive or when the light comes on change the brakes in the next week or two.

On my 2010 6-speed manual Golf TDI, I got new front and rear brakes and rotors at ~145,000 miles. They really do last a very long time!

the tdi wagon has very large brakes stock for the weight of the vehicle, so assuming you don't abuse it you can probably expect 100000 miles out of the components, at least thats what I saw. I do travel and after parking for a few months in new england winter I needed to change my rotors and pads, they do seem to rust very fast if you are not using them.