The weight of troubleshooting is completely different when you drive with the expectation that trouble will occur in your local area,and when you go far and cause trouble. Basically,no matter what kind of work you do,whether it's changing a tire or anything else,replacing something means that your car will go from being running well to not being able to run,even temporarily. Maintenance is about changing your body from a state where you can't run to a state where you can run better than before,or a state where your endurance is higher than before.