Quality is free, in the end, but it requires a reallocation of resources so that defects are prevented cheaply instead of fixed expensively.

Not all quality-assurance goals are simultaneously achievable. Explicitly decide which goals you want to achieve, and communicate the goals to other people on your team.

No single defect-detection technique is completely effective by itself. Testing by itself is not optimally effective at removing errors. Successful quality-assurance programs use several different techniques to detect different kinds of errors.

You can apply effective techniques during construction and many equally powerful techniques before construction. The earlier you find a defect, the less intertwined it will become with the rest of your code and the less damage it will cause.

Quality assurance in the software arena is process-oriented. Software development doesn't have a repetitive phase that affects the final product like manufacturing does, so the quality of the result is controlled by the process used to develop the software.