Engine pressure washing
Though this may seem as a good idea to keep the engine bay clean, it is certainly not. The engine has a lot of sensitive components which may be exposed. Subjecting such components to high pressure could result in something coming loose or breaking.
Improper tyre maintenance
Tyres are the most neglected part of a car. Most people don’t bother checking to see if they are okay or not. Some people continue to use worn out tyres because the car is still running. However, a bald tyre generates more heat due to friction and has more chances of blowing out if used over longer distances. It can also cause your car to hydroplane if there is any water.
Engaging reverse in a moving car (For automatics)
This is something very tough in a manual car, however in an automatic car, it is easy to do. Engaging reverse gear while your car is still moving forward or doing the opposite will put a lot of stress on your transmission and will accelerate the wear & tear on it. Each transmission has gears inside it. So when you shift from reverse to drive (or vice-versa), the irection of rotation of the gears is reversed. If you do it while the car is in motion, it will make the gears act as a brake which will certainly cause damage. It may even damage the drive shaft.
Ignoring funny noises from car
Is your car making some funny noise that it wasn’t earlier? It is a sign that something isn’t right. It may or may not be life threatening, but it certainly means that there is something wrong. Get it checked.
This will shorten the life of your clutch. What your clutch does is transfers the power from the engine to the transmission. When you ride the clutch, it means that the engine isn’t transferring all the power to the wheels. So what that means is that the engine continues to produce as much power as it did, but only a certain part is being transferred to the wheels. The remaining part is being taken in by the clutch, which will just cause excessive wear.