Selling reusable products is important to leverage your customer base. That is a lot easier than finding 100 new customers each year. An example that loosely fits this criteria is Life Insurance, because of the comssion structure, which will usually continue to pay the sales representative for the life of the policy. Examples of non-reusable products are most clothes, cookware, and tools. Low sales quotas.
Most companies have some kind of minimum production.
As mentioned, they have carrying costs for each member, and if members aren't producing, they are unprofitable. So direct sales companies have to drop non-producers from the roasters. However, quotas should be reasonable. Take the Shiny Teeth Company example. If they require you to buy more toothpaste than good oral hygiene requires, that would be unreasonable.