This one answers 'what should I spend on next'. If you want the maths on how many rolls an item takes, use the roll odds calculator instead.
Finish the tutorial, turn AUTO ROLL on, and spend your first credits on planet rows. Before your first long session, redeem the live codes and join the developer group — that is free potions plus a permanent +3 Luck, and both take two minutes.
FAQ
Because the game does not expose them. We have read the panel values people care about (rebirth multipliers, ladder multipliers, prices), but how every luck source combines into the displayed figure is not printed anywhere yet — so the advice sticks to priorities that hold regardless of the exact maths.
This one tells you what to spend on. The roll odds calculator does the probability maths for a specific weapon using the rates the game prints on the feed.
They place you on the progress map — the planet ladder zones and the rebirth bands we have observed — and the advice matches that position. They are not formulas and will not output a number to beat.