_Substitution More General in the Case of New Consumers._--The substitution of a cheapened article for others is the dominant fact in the case of new consumers of such an article, while an increased consumption of other things sometimes occurs in the case of old consumers. This does not have as large commercial effects as the other change. If we produce cheaper shoes, we make it easier to acquire good ones, and those who formerly contented themselves with an inferior kind take a better one. That means that they add to their purchase lists the higher utility which is present in the one grade and absent in the other. They buy a new element in goods rather than more of those goods, and while they may not always change their consumption of articles of other kinds they more frequently do so. Those who begin to use something which formerly they went without altogether usually give up the use of some good or some quality in it, or get on with a smaller quantity of it in order to make the new indulgence practicable. The man who, when bicycles became cheap, bought the first one he ever owned probably gave up some other gratification. _How the Sale of Goods which wear out in the Using increases as the Price Falls._--When goods deteriorate as they grow older, users have to buy new ones often if they are not willing to use those which are worn out and inferior. If we want always to wear clothes of good quality, we refrain from wearing a suit too long. We discard many things when they have somewhat deteriorated, and this forces us to buy, in a term of years, a larger number of them than we should otherwise do. We discard carpets and upholstery early when they are so cheap that we can afford to do so. We thus improve our goods qualitatively by adding to them quantitatively. _Substitutions a Protection for Labor against Undue Displacements._--Now, not only are the substitutions we have cited of commercial importance, but they act in the direction of retaining labor in a group where "labor saving" has been effected. They help to prevent this process from being equivalent to labor expelling in so far as either a general group or a subgroup is concerned, since they increase the social demand for the products of the group in question and cause a relative diminution of the demand for other things. Quite evidently there is, for these reasons, the more need for labor within this group and less need of it elsewhere. Cheap shoes may thus never mean fewer shoemakers and cheap watches may not ever mean fewer watchmakers.