Slime Trader’s rebirth resets the stage but keeps the defense you built

Slime Trader’s reset does not advertise a return to an empty defense. The developer says rebirth returns stage progress to 1-1 and grants points for rune draws, while keeping your slimes, gold and summon cost intact. Those named exceptions define the decision better than the word “rebirth” alone.

You are comparing a reward with the progress through stages that must be made again, rather than assuming every investment disappears. The listing does not supply the reward formula or time required to return, so it cannot establish a best moment to reset. What it does establish is which pieces of the setup remain available.

The defense itself is not fixed merely by its grades. Two same-grade slimes merge into a stronger one, but the developer says a merge can change the resulting type. That gives another reason to inspect the actual formation you retain: grade and attack style answer different questions.

If incremental resets usually leave you wondering what is being thrown away, start with this explicit persistence rule. Then examine whether the rune draws change the defense enough to justify repeating its early stages. Trading is also advertised, but it supplies no basis for treating a retained slime as a guaranteed financial return.