Q&A for How to Extend the Life of Your Car

Aside from the obvious risk of running out, it's generally a good idea to keep your tank at least half full, because the fuel in the tank actually helps cool your fuel pump. If you're always running near empty, you could be in need of a new pump sooner than expected.

Yes, the trips are often not long enough to warm up the oil in the engine so the oil doesn't lubricate the engine as efficiently. If you have a modern diesel car, they come with a particulate filter which prevents soot (unburnt carbon) from escaping through the exhaust. These filters regenerate on long journeys because the exhaust is hot enough to burn off this carbon, but this process simply doesn't occur at lower temperatures (e.g. short driving).

An internal oil leak is most likely. Often, this means oil is entering into your combustion chambers (often the result of failed valve seals or other valve components) and burning along with your gas. Have any oil leaks checked out by your authorized service provider.

No. the longer it idles, the more carbon builds up, shortening the life of the car.

Take it to a mechanic and have it checked. A good tech should be able to help you in answering of all of your questions. There is no simple answer, though, it depends on many aspects: your car history, maintenance schedules, as well as your driving habits, etc.