Asphalt goes through a constant state of oxidation after it is laid. The hot rays from the sun slowly leach moisture from the driveway. One of the first signs of oxidation is that the driveway will fade from the color of new blacktop to a dull gray. This color change indicates that you need to seal the driveway. A product designed to seal the driveway and protect it from UV radiation helps prolong driveway life.
Moisture, frost and shifting ground all cause cracks in a driveway. If you get a crack, patch it immediately to keep the driveway sound and to prevent the crack from worsening, which it will likely do if left unattended. Using a patching compound made out of three parts gravel -- two of sand and one of cement -- to patch a driveway crack makes a strong patch that will hold up under the weight of your car.
You may worry about fluid stains on the driveway. Oil will stain a driveway, but over time the stain will fade or get covered up with additional coats of sealer. Gasoline is a much larger concern. If you spill gas on a driveway, it degrades the concrete and makes it soft. The area affected won't harden naturally and will need to be fixed by a professional. Don't fill any vehicles or yard equipment with gas while parked on a driveway.
A driveway with drainage problems creates issues that aren't just confined to the driveway itself. The yard and the house also face potential damage if the driveway is pooling water in the wrong location, or worse yet, draining it towards the home. If this happens, the grade of the driveway needs to be corrected or a drainage system of some type installed to deal with the excess water.