Read your current rebirth panel before resetting. A Jul 27 recording showed a first gate of $75K plus a Rare Slime, with +10% Money Bonus, Lightning Keyboard and +2 slots listed as rewards.
Rebirth is a reset milestone rather than a routine purchase. Roblox officially describes the Rebirth! badge as being earned by rebirthing for the first time. A Jul 27 gameplay panel supplies a dated example of the first decision: $75K and a Rare Slime were shown as requirements.
The same panel listed a +10% Money Bonus, Lightning Keyboard and +2 slots as rewards, and it warned that progress would reset. These details are valuable for preparation, but they are not a permanent contract. The live panel can change after balancing updates, and later rebirths may have different gates.
That uncertainty is why this page does not calculate a universal best rebirth time. A timing formula would need current earning rates, reset scope, requirements and reward stacking. Instead, compare your current panel with the dated snapshot and decide only after the required item and cash are both clearly confirmed.