That only works for "app as a product" deals, in which someone pays you to deliver them something. For many (most?) cases, the development is continuously ongoi

That only works for "app as a product" deals, in which someone pays you to deliver them something. For many (most?) cases, the development is continuously ongoing, you have a salary and work as part of a team. Clear code with tests makes development more efficient, and is a better use of your employer's dollar.