I run a '95 manual 300tdi. Had it for about 12 years and in that time it's been numerous times around Europe. It's been off-roaded, up ski maintenance trails (in the summer) with 5 people on board and four bikes hanging off the back, plus fully loaded with camping gear. It's pulled over about 60 leylandi trees with the winch. Driven into a flooded ford to tow out another stranded vehicle. Got me home in the icy winter when other vehicles have been stranded (much to the annoyance of the other drivers). Rescued people from the top of a mountain who had misjudged their timing for the descent, in Italy.
It's upto 190,000 miles now and I would guess it's been towing for about half of its life: caravan, trailer with mini-digger/tractor/sand/gravel, other vehicles. So, it's had a hard life.
Sure, things have gone wrong, I had the Zeus timing conversion kit soon after I bought it, so never changed a cambelt on it. (It doesn't have one)
Two headgaskets and one replacement head, so far.
The one head gasket was while towing a Series 3 about 100 miles.
It still got us home (both vehicles) even though it took about 10 hours stopping to let it cool and top up with water.
It's had a couple of 50mm square patches welded on each rear wheel arch a couple of MOTs ago, and the boot floor will need doing some time soon.
It's had a new heater matrix, that was fun, and a new radiator.
But it's still starts every time and runs fine even if it looks like a tired old knacker. Do I care if it gets another 'trolley scar' in the supermarket carpark? I doubt if I even notice it.