When you work up to Singularity the first time it warns you that it will restart the simulation. When the simulation restarts you are back to the beginning but you also accrue metabits(?) which can be used to change game parameters such as speed of simulation. What can be changed is given in another concept tree that you can get by tapping on the pink megabit counter at the top of the scene. Not wanting to restart again I have let the megabits pile up. I can only see a use for about 50 megabits on the tree but I now have 300 stored up. Is there particularly good time to bite the bullit, stop the simulation and make changes?