Would vs. Used To
What is the difference between says “I would” and “I used to” when talking about past habits. Someone suggested to me the difference is that “I used to” expresses an event that had regularly occured while “I would” expresses something that happened only occasionaly. However, this does not seem to be true in all cases. The particular sentence I was confused about is this:
When she was young, she would sing at the church. When she was young, she used to sing at the church.
In either case the frequency which she sang at the church is not specified. So what is the difference?