What’s the Truth about . . . Checking Tefillin?

 https://jewishaction.com/religion/jewish-law/whats-truth-checking-tefillin/

 Fact: The halachah is that tefillin that have been checked and found to be kosher and are then used regularly are not required to be rechecked. Nonetheless, as a stringency, various customs have arisen regarding how often they should be checked.

 

I was told that Rav Moshe never checked his tefillin but his family took them and had them checked anyway