dont always use idempotency keys for POST requests, but it's a good idea most of the time.

hey folks, ive been thinking a lot about POST requests lately, especially in distributed systems. we all know POST requests can have side effects, and we want to avoid accidental duplicates. using idempotency keys is a common pattern. but is it always worth the extra complexity? what are the trade-offs of *not* using them, and in what scenarios might that be acceptable? keen to hear your thoughts and experiences.