SuGoiSuす語彙すGrammar › N2 · 06 Extent and degree
〜につれて: as ... changes; along with
N2 · 06 Extent and degree
Says that as one thing changes gradually, another changes with it.
Verb dictionary form or noun + につれて. Both parts are gradual changes, not one-time events: 時間が経つにつれて. The second half must be a change and not the speaker's intention or command. Written or spoken.
Examples
時間が経つにつれて、痛みは薄れていった。
As time went by, the pain faded.
日本語が上達するにつれて、友達も増えた。
As my Japanese improved, my friends increased too.