Idempotency keys: Are they overkill, or actually essential for keeping APIs safe?

hey all, been thinking about api design lately. network glitches happen, you know, and sometimes a request might get sent twice. to prevent duplicate actions, especially for things like creating orders or processing payments, using idempotency keys seems like a good idea. but is it always necessary? for simple get requests it's obviously not needed, but for post, put, or delete, when do you draw the line? are there specific scenarios where implementing idempotency adds too much complexity or overhead compared to the risk of duplicates. i'm curious to hear your experiences and thoughts on this.