1999 Nissan Altima How long will I have

It is very difficult to say how much you will get out of a car because there are some many variables that go into automotive health. First thing when looking at a used car is ask for service records. If the owner provides you with a stack of service, and repair receipts you can assume the vehicle has been well maintained. Also ask how often the oil has been changed. Is it at every 3000 or 5000 miles, or is it hard for the owner to say? If the owner can't tell you the last time the oil was changed this is a bad sign. When is the last time the vehicle was tuned up, belts replaced, fluids flushed, etc? Also look at the interior and exterior. Is the vehicle beat up inside and out or does it look like it has been cared for. Also look under the vehilce. Does the undercarriage look wet? This will indicate leaks. Also look at the tires. Are they wearing evenly or are they bald on the inside or outside? This can indicate suspension and steering issues.