ELSO CA Testing question

[Koresample]

I just started using this test kit for my calcium. In the instructions, it gives directions for both an 'approximate' and an 'accurate' test procedure. The difference being one is within 50 mg and the other 10 MG accuracy. It says you can use the 'approximate' one to save on use, but to do the accurate one, you have to do the first one regardless in order to get it more accurate. My questions is this, for those that use this test, how often do you test, and do you always do both, or just the approximate one?