It is a tool to leverage when appropriate. You can write tests when prototyping or you can borrow a little tech debt and skip the tests during the prototyping

It is a tool to leverage when appropriate. You can write tests when prototyping or you can borrow a little tech debt and skip the tests during the prototyping phase. At this stage it is like a line of credit. Then, as the feature/product starts to take shape, you can pay down the debt by writing the tests and refactoring the code to be simpler. This would paying off the line of credit. Or, you can roll the line of credit into a term loan and move on. This will increase your long term debt.