Fortunately for me I have no intention of going out in the wilds with my Td5. Nowhere in Western Europe is more than a phonecall and an overnight delivery away from spares!
I remember when Td5s first came out, there were widespread predictions of doom and disaster with people saying the electronics would fail and leave people stranded. As far as I'm aware it just hasn't happened, though.
We had a 1990 200 Tdi for 10 years before we got out Td5. It was fine, but I wouldn't willingly go back to one, unless it had been pretty comprehensively restored.