While the meaning of 代える seems rather straightforward, the other two at times delude me. When should one be used over another? Are there any situations where both 換える and 替える are applicable?
Here's how I understand them
The idea here is that there is some kind of reciprocation. Agent A gives something to agent B, and agent B gives something back to agent A.
The truth is, there is a lot of overlap, so it's not always so easy to decide which is most correct.