I think you are (understandably) not responding to the whole quote. It says not to put a "speed hack" in until you know where the bottleneck is. That doesn't s

I think you are (understandably) not responding to the whole quote. It says not to put a "speed hack" in until you know where the bottleneck is. That doesn't sound like what you described at all. If you're making a video game with tons of physics objects and you know for sure from experience that collision detection is gonna be a major problem, and this is what you're pushing the limits on, I don't think it's a "speed hack" to design the game and its systems around this. Additionally, if you're working on something that you know is gonna be a big performance concern then you definitely want to measure it! Not to find out if it's a concern but to find out how successful you are at dealing with the concern.