Does a person have to keep checking his ritzuas and battim to make sure their black or his he יוצא as long as פרשיות are כשר
A person has to make sure that the ritzuas and batim of his tefillin are indeed black, and it is not enough that the parshios are kasher. This is the same as our need to have a healthy brain, but also a healthy heart, kidneys, lungs and liver. We can’t just be יוצא with one of them.
Check them and make sure that they are black, but you don’t have to constantly check them. But once in a while you should keep an eye on them to make sure that they are still black.