At least as important for software quality is: 3) Make extension of thorough automatic testing in all levels of the testing hierarchy as effortless as possible

At least as important for software quality is: 3) Make extension of thorough automatic testing in all levels of the testing hierarchy as effortless as possible. Nobody is going to bother with thorough testing if it takes a day to add a simple test case for the new minor thing they just added in the last half an hour. Boom, test hole, disaster waiting to happen next time somebody refactors something. No matter how great you are doing with 1) and 2).