Well that's just it - if you're running into slowness that's going to effect the core of what you're building optimizing it isn't "premature". If you're fiddli

Well that's just it - if you're running into slowness that's going to effect the core of what you're building optimizing it isn't "premature". If you're fiddling with getting a rarely used subsystem to load in 50ms instead of 60ms that's premature.