It has been said elsewhere that there are many things that affect Engine longevity, so without stating the obvious, this is just a statement of one Engine's experience over the last 10 years. (Spoiler - the main driver isn't me - it's my partner)
Our 2010 2.0 TDI is just 300km shy of its 315,000km service. All scheduled services were carried out by VW up to 180,000km then by local workshops.
The story about the workshop change involves an engine warning light diagnosed as a secondary water pump fail at 186,000km. VW wanted most of my life savings to rectify (quoted about A$3,000) so I asked around. Through a friend of a friend (lets call him Jarrad) I received advice that I thought was sensible - if there are no other warning lights for oil or temp, it's probably just a sensor fail so keep driving but be watchful.
Followed Jarrad's advice until the next scheduled service was due at 195,000km. Went back to the workshop that employed Jarrad. He suggested I not only replace the water pump, but also put a new timing belt and kit in at the same time, because the belt was shortly due for replacement anyway. (VW had said nothing to me about the timing belt requiring replacement at the next service - no doubt that was a future profitable job as far as they were concerned) so the water pump and timing gear were replaced at the 195,000km service for just a little over A$4,000 for everything. I continued scheduled servicing with this workshop until the 255,000km service.
At 262,642km another engine warning light - this time because the EGR valve had coked up and the engine software said No - only limp home mode allowed. That was about 160km from home on a return journey through a National Park area without phone coverage! We limped for about 80km until we could get road service and even then we had to continue in limp home mode as roadside service cannot do much about a faulty EGR. At this time, Jarrad had moved on from the workshop, but I consulted him anyway and he suggested the workshop was not using an oil that matched VW specifications which could be the cause of the high level of deposits in the EGR valve. Note here from self - I do not know if the EGR should last longer than 260,000km but as far as the service records show, it had not been replaced during earlier servicing.
Shortly after this, a chance meeting with an old school friend led to me finding another workshop, run by someone I went to school with. I took Miss Tiggy there for her 270,000km service and learned a few more lessons. The replaced EGR valve was only retained by two of the three bolts that hold it in place. My new mechanic showed me the back deposits building up around the missing bolt where gases were escaping. He removed the EGR, cleaned and replaced it using three new bolts. He also showed me the VW spec oil he uses for all VW servicing (no corners being cut) and confirmed Jarrad's opinion about the wrong oil use was very plausible.
I now drop the car off in the afternoon, it gets put on the hoist and the oil drains overnight. The oil pump is also vacuum sucked to remove all old oil. The remaining part of the service is carried out the next morning. The car is vacuumed, windscreen washer bottle filled, windscreen cleaned and tyres blacked. Although the cosmetic stuff doesn't affect the engine, that attention to detail carries through to all work carried out on Tiggy. Besides, my partner likes the condition in which the car is returned.
To round off the story, the only other non-scheduled servicing carried out has been an air-conditioning re-gas (186,000km), replacement of rear trailing arm bushes (225,000km), replacement of front strut bearings (at 300,000km service) and replacement of damaged front left ABS/Brake wear indicator wiring loom (recent - still waiting for the invoice).
I am only a casual driver of Miss Tiggy - my partner is the true owner and she is very happy with the last 10 years ownership. If she is happy - then so am I, but I still think two wheels are better!