GRAMMAR DETAIL

〜てからというもの

ever since

Emphasizes that a state or habit has continued up to the present since a particular event or change.

Examples

部署を移ってからというもの、彼は毎朝早く出勤するようになった。

Ever since he transferred to a different department, he has been coming to work early every morning.

引っ越してからというもの、近所の人とよく話すようになった。

Ever since I moved, I have often talked with my neighbors.

Structure: Attach からというもの to a verb's te-form to emphasize a changed state or habit continuing from an event onward.
Basic usage: 部署を移ってからというもの、彼は毎朝早く出勤するようになった。 means that transferring departments marked the start of his continuing habit of coming to work early every morning.

One-off sequence versus lasting change
- 引っ越してから買い物に行った places a shopping trip after moving. 引っ越してからというもの suits a continuing change in life or habits that began with the move.