In Korea, it’s perfectly legal to secretly record conversations that you are a part of. (It’s only a crime when you secretly record conversations you aren’t a part of. No leeway here!)
The rationale is similar to how you get to keep a record of all email exchanges that you were a part of. (But not of email exchanges strictly between others.) And anything you say to another person is not intended to be “secret” at least vis-à-vis that person.
Recorded conversations often play a vital role as evidence in court. So it’s generally a good idea to record conversations where you’re being promised something important. Or, you’re making a formal complaint to somebody. Or, you’re officially informing someone of something. Think in terms of: “What if he/she denies such a conversation ever took place?”
At the same time, keep in mind that (in Korea) your conversation-partner could be recording what you say too. Picture everyone you talk to wearing a wire.
There are apps that automatically record all your phone conversations. Another useful feature is the “airplane mode.”
Q: If a tree falls in a forest and no one is around to hear it, does it make a sound?