I use to use a preamp that allowed for polarity inversion by remote control so that one can easily A-B the difference. In my system, the effects of flipping polarity varied greatly, depending on the particular recording. In most cases, the change is subtle and whether one or the other polarity was better was not clear cut. For example, even in one particular cut, one polarity may make the vocalist sound more "present" but the piano might sound slightly "phasey." It might well be the case that polarity is not consistent between different parts of the same recording. My preferred polarity, when I bothered to listen for this, varied from recording to recording, so it would make no sense trying to set up a system to consider polarity; if that is important to you, a switch of some sort would be needed.
You can buy test CDs that have music presented in two different polarities so you can hear for yourself it matters. One example is the Jazz sampler/test CD from Chesky Records.
You can buy test CDs that have music presented in two different polarities so you can hear for yourself it matters. One example is the Jazz sampler/test CD from Chesky Records.