Would you mind providing examples for each case? That is, code that you deem laggy, profiling it, with tick() for example, showing us the output, optimizing and using an alternative, profiling it again, and compare the results, also providing everything so we and roblox can reproduce (example). I don’t usually follow rules of thumb like these, because the engine is subjective to changes that may reaffirm or invalidate some cases. Also because you could have another worse case somewhere else that is dropping your FPS below 60, but you still keep optimizing the wrong code!