I changed mine at about 2yrs 6 months, which was late according to VW's recommendation. Brake fluid absorbs water and degrades over time. Knowing that German engineering typically doesn't plan for the wide tolerances that we are accustomed to in the USA, I decided to follow the mfg recommendation.
If you're a DIY'er:
I used a Valvoline synthetic brake fluid that exceeds DOT5. The specs were in excess of the Pentosin OEM stuff. The flush took a bit more than 1 qt, so buy two. I also bought a nifty tool for $5 that was basically a tube fitting to go over the bleeder with a check valve at the end. It allowed my to bleed the brakes single-handedly. Don't let the master cylinder go dry!
