The lug nuts need to be secure so that they don't become loose over time and fall off. So you want them to be placed tightly with a torque wrench. The problem of being unable to loosen them later is due to the fact that appropriate lubricants weren't applied before the lug nuts were put in place originally. When you have tires replaced/rotated/balanced, ask the shop to be sure that the wheel is properly lubricated before the lug nuts are tightened. Later, you should be able to loosen them yourself with a lug nut wrench.