I have heard the “premature optimization is the root of all evil” statement used by programmers of varying experience at every stage of the software lifecycle, to defend all sorts of choices, ranging from poor architectures, to gratuitous memory allocations, to inappropriate choices of data structures and algorithms, to complete disregard for variable latency in latency-sensitive situations, among others.
Read more: http://joeduffyblog.com/2010/09/06/the-premature-optimization-is-evil-myth/