につれて・に伴って・に伴い: the difference
につれてN3
Meaning
As…then, In proportion to,
Past papers
Tested 3 times in past papers
Example
日がたつに連れて、怪我が悪化してきた。
As the days go by, my injury gets worse and worse.
に伴って・に伴いN2
Meaning
As, Due, Along with, Hand-in-hand with, Resulted in, Be consequent upon
Past papers
Tested 2 times in past papers
Example
気温の上昇に伴って、植物が一斉に芽を出し始めた。
As the temperature rose, the plants all began to sprout.
How to tell them apart
「につれて」: things change together naturally, as time goes by.
「に伴って」: focuses on cause and side effects of a big event; the most formal.