What is the proper phrase to express familiarity with frequent changes?

The phrase "just as" effectively conveys a sense of familiarity with frequent changes because it implies that changes are happening simultaneously or in correlation with another event or action. This phrase can indicate that the speaker recognizes the continuous or recurrent nature of the changes in relation to the situation being discussed. It sets up a comparison or a context where one is accustomed to change occurring alongside other developments.

In contrast, the other phrases do not carry the same meaning of familiarity with changes. "Just before" refers to a time leading up to an event, while "just after" highlights a moment following an event, neither of which suggests an ongoing or habitual awareness of changes. "Just during" focuses on a specific time frame but lacks the nuance of being accustomed to or familiar with the frequency of those changes. Therefore, "just as" is the most appropriate choice for expressing familiarity with situations that involve constant or frequent changes.