The no brainer to keeping your car in great shape is never skimping on maintenance, ESPECIALLY if it is german. By far one of the worse things you could if your car has an interference engine is not change your timing belt in on or before the recommended time. If it snaps, you are so royally screwed.
I do pretty much all my servicing myself..For the same cost or lower, i end up putting in the highest quality parts I can find and never cutting corners on the work. With the internet and enthusiast forums, it’s really pretty easily to diagnose common issues and do service. Also usually, someone ends up having some tool that you can borrow from.