How Effective Is Retrieval Practice for Halting Forgetting?

There's a sense in which retrieval practice and the mnemonic medium are just flashcards, right? Although I have just in scare quotes there because they're actually incredibly impactful and useful. It is apparently more or less possible to find parameters of retrieval practice which will essentially halt forgetting for pretty much anything you could care to learn. Some things do require more practice than other things; often it's possible to kind of refactor the cards in order to make it cheaper. But let me say instead that for on a practical basis for everything I've tried,  it's possible to use retrieval practice to reliably remember it with relatively low cost. So yeah, okay, right.