In practice, rolling your own strengthened/salted hash is probably fine if you use a decent hash function, but why bother? The code already exists to do it for

In practice, rolling your own strengthened/salted hash is probably fine if you use a decent hash function, but why bother? The code already exists to do it for you, and using a standard function allows for better interop and portability. It will also (likely) have been designed and/or checked by people with domain knowledge, and so is more likely to avoid subtle attacks - just repeating a hash function n times might not offer the security you expect (e.g. 2DES is barely any stronger than a single DES pass - you need 3DES to make much of a difference).