Ah, that sounds like the situation with my daughter, too (up until 2.5 years old when we moved). Around this time she also started climbing out of her crib, so we changed it into a bed, which made it easy for her to just run out of her room and into ours whenever she woke up at night.
We did both methods (waiting and CIO). Now it’s a mix of two. Sometimes crying helps her get tired so when we come back to the room she’ll be (finally) sleepy enough not to notice when we leave the room.