ever since ~
Expresses a lasting change or state that has continued ever since a specific event or action took place.
This pattern emphasizes that something started at a certain point and has continued without interruption up to the present. It is used when the speaker feels the change is significant or permanent. It often appears in narratives or formal statements, and the second part of the sentence usually describes a resulting state or habitual action that persists.
The nuance is stronger than just saying 'since' (てから). It implies that the event was a turning point, after which things changed dramatically. It is not used for trivial matters; rather, it marks a clear before-and-after contrast. This pattern is more common in written language or formal speech, and less common in everyday casual conversation.