It's easier for a bug to slip in, like an off-by-one error, when one chooses to write a loop rather than invoke a well-tested abstraction that hides the loop, l

It's easier for a bug to slip in, like an off-by-one error, when one chooses to write a loop rather than invoke a well-tested abstraction that hides the loop, leading to more time spent later in the development process debugging and fixing the problem.