There are many actions you can take to not waste money on your car. This is distinct from what you should do with regular maintenance to keep it reliable and safe by servicing it properly. One of the simplest ways to save money is to make your car last longer.
From time to time, I will be sharing nuggets of wisdom gained from many years in the auto trade - not as a mechanic but as a successful salesperson who enjoyed (mostly!) over 15 years with the same organization in Germany. I have witnessed much craziness and benefitted financially from the behavior of my car-buying public. I have also made many car mistakes, some of them expensive and from which I have learned lessons I will share later. Let's make the first one simple, REALLY SIMPLE.
Tip 1 - When starting your car, especially from cold, let it idle for 10 seconds before driving away.
Rationale: When you haven't run your car in a while, especially from the first start in the morning, pretty much all the engine's lubricating oil is sitting in your oil pan or sump. As your engine turns, the oil pump pushes oil around your engine, so that the moving parts, especially cylinders and valves are properly lubricated. Starting and driving off straight away will cause unnecessary wear as non-lubricated or under-lubricated metal rubs against metal, causing premature wear under load.
Add 100,000 miles or more to the life of your engine with this one simple action.