It may not be practical to buy the same tires as before -- a few years from now, the tires being sold may be different, even if they have the same or similar name. Also, the new model tires may be better than the old ones that you are replacing.

Here is another thing to do with the spare: if you have a 245 wagon, place the spare so that the valve stem is reachable without removing the tire. You can then check the pressure and add air (if necessary) conveniently.