What is the effect on society of me choosing to make my own shoes, food, or clothing? This question comes from someone who suggested brushing my teeth benefits the economy because it reduces demand for dentists, lowering the price. However, when I think more generally of making my own shoes/clothing my decrease in "clothing-services" leads to an increase in demand for the raw materials, in this case fabric. (I am ignoring the time it takes to learn how to make clothing.) Or suppose everyone simultaneously decided restaurants were unhealthy and started cooking at home; the restaurant industry would collapse, but would agriculture stay the same?

Is the economy the same, worse, or better when a consumer switches from buying a good to buying the raw materials for that good to manufacture it themselves?
The consequences "on society" of you changing any consumption/production choice you make is zero. Assuming that all the markets you interact with (shoes, clothes, etc) are competitive, your contribution to the demand and supply of a good/service is neglectible. Therefore, market equilibrium (price/quantity) will not change.

The story is of course different if everyone, or a "sizable" amount of people does change their decisions. Demand and supply of goods and services will be altered, just as the supply and demand of all the inputs used to produce such goods. Since a lot of goods and services are related in one way or another, either as complements or substitutes, the consequences could be felt accross the whole economy. How far this goes, depend on the number of people changing their actions, and the relation between goods, services and inputs. In short, your actions will have a general equilibrium effect.