Unless you are seeing problems in the tank, with the plants or fish, there is really no reason to worry about what the pH is. Most of the tests we can do are useful when there is a nagging problem that we can't seem to get a handle on. Other than that, those tests are either fun to do, or not worth doing. And, pH is one of the main tests that really doesn't tell you anything that the tank isn't telling you by how well the fish and plants are doing. This wouldn't be worth mentioning except that when we obsess over pH and start doing things to "fix" it, we generally will be disrupting the life in the tank, and most likely doing more harm than good. So, why do it?