> The important part of "premature optimisation is the root of all evil" is PREMATURE. Right -- I think the examples he's arguing against have slightly misunde

> The important part of "premature optimisation is the root of all evil" is PREMATURE. Right -- I think the examples he's arguing against have slightly misunderstood what "premature" means. The quote is supposed to mean, "Don't optimize until you know that optimization is necessary." The people in his examples are interpreting it as, "Don't optimize until your program is feature complete". I doubt Knuth would agree with that principle. If people are raising tickets saying that some feature is slow, then you know optimization is necessary, and it's not premature any more. That said, as with any proverb, you have to use some common sense. If you know you're going to be doing key-value lookups in a data structure that's going to contain hundreds of thousands of pairs, it's OK to start off with a hash table, rather than starting with flat list + linear search and switching over only after benchmarking.