It's about getting the engine to operating temperature and a decent run every so often. Short runs would be 10-15 miles. If this is for urban commuting, that's when you get into issues, start-stop, etc. At some point the EGR valve will clog - that's inevitable on diesels. In addition AdBlue is known to weak point, as it uses integral tank with pump and sender. I've started using Forte anti-crystal on every AdBlue top up. You can also use Forte fuel conditioner (for diesels) straight in the fuel tank on a quarter full and drive it like you stole it for 15-20 mins. The fuel filter needs changed, so do this every 20k miles. Helps clean injectors, etc. Also treat the car to premium diesel. Older Euro 4 diesels could be used for short run journeys, but eventually intake manifolds get carbon build up, or sticky vanes on the turbo. Euro 6 - the engine is regenerating anyway, which is where the engine heats up to effectively burn off soot via DPF. These cars tend to be sensor heavy, so irrespective of whether you're spanner handy, I'd advocate getting VCDS (via Gendan), as the car will store logged faults. Main dealer will charge you £200 minimum for scan. In fact - it's worth even checking any perspective new purchase. Logged or stored faults will remain unless cleared. Usually referred to as DTCs. If you are spanner handy - then things like retracting rear electro-mechanic handbrake, priming fuel pump and relearning motors such as panoramic sunroof are useful to have. Audi also use ODIS dealer level software. Controls programming features, security, etc. I know for example that even Golf Mk 8 - you can't service rear brakes without it. Sign of things to come I'm afraid. As chains and tensioners are at the back of the engine - then it's an engine out job to replace, along with plastic guides. Should be good for the life of the engine, but where they get camshaft sprocket wear or chain slap is on cars that were on long-service regimes (up to 18k miles) between oil changes. Look carefully at the service history and avoid anything that's not been serviced at up to 10-12k mile intervals. No oil can maintain viscosity and lubricating qualities at that sort of mileage. Audi will tell you different, but this was brought in to satisfy fleet managers trying to reduce costs. Most of these cars were 3-4 years old on finance deals, so bill is normally picked up by next unsuspecting owner down the line. Tiptronic boxes do have a ZF service kit - so if not done I would get this done at 60-80k miles for peace of mind. Front and rear diffs usually good up to 100k miles.