Hence the winter sales are constantly growing larger and the seasonal demand is in part lifted from the dealer. And he finds it profitable to buy ahead in anticipation of needs. Thus we have no seasons in the plant; the production, up until the last couple of years, has been continuous excepting for the annual shut downs for inventory. We have had an interruption during the period of extreme depression but it was an interruption made necessary in the process of readjusting ourselves to the market conditions.
In order to attain continuous production and hence a continuous turning over of money we have had to plan our operations with extreme care. The plan of production is worked out very carefully each month between the sales and production departments, with the object of producing enough cars so that those in transit will take care of the orders in hand. Formerly, when we assembled and shipped cars, this was of the highest importance because we had no place in which to store finished cars. Now we ship parts instead of cars and assemble only those required for the Detroit district. That makes the planning no less important, for if the production stream and the order stream are not approximately equal we should be either jammed with unsold parts or behind in our orders. When you are turning out the parts to make 4,000 cars a day, just a very little carelessness in overestimating orders will pile up a finished inventory running into the millions. That makes the balancing of operations an exceedingly delicate matter.
In order to earn the proper profit on our narrow margin we must have a rapid turnover. We make cars to sell, not to store, and a month's unsold production would turn into a sum the interest on which alone would be enormous. The production is planned a year ahead and the number of cars to be made in each month of the year is scheduled, for of course it is a big problem to have the raw materials and such parts as we still buy from the outside flowing in consonance with production. We can no more afford to carry large stocks of finished than we can of raw material.