for most positions training a "green" hire is probably like 20% new, transferrable skills (PLs, frameworks, etc.), and 80% highly specific, and less broadly applicable domain knowledge. That includes things things like figuring out your process, or even who to go to for what. Besides, the best employees probably are the ones that want to learn new things, so if you land the perfect candidate that doesn't need any "training" he might be more likely to leave since he's probably doing the same "boring" thing he was doing at his last job...