The trap: there is no hidden "five losses and you are out" counter. The life bar and the day number are the only resources that matter. A run that "only lost twice" can still be dead after two day-5+ fights.

The Life Cost Table

DaysLives lost per defeatWhat it means
1-21Cheap experiments. Reroll for pairs, spend lives if a fight buys a merge.
3-42Stop buying a zoo. Commit to a recognizable engine.
5+3Curiosity purchases are how championships get donated.
Second Chance (once per run): the first time lives hit 0 you are put back on 1 life and a reward event opens. The next empty bar ends the run - no second revive, no reset to 10. A late 3-life loss after Second Chance is just a slower defeat.

1Spend Lives So You Reach 10 Wins

2When Second Chance Triggers

"Only lost twice on day 7"
Wrong resource
Two day-5+ losses are 6 lives. Count the bar and the day, not the loss counter.
"Reroll 3 gold after day 5?"
Only to finish a merge or core
A miss after day 5 is often a donated 10-win. Greed the Second Chance event for a Mythical only if the board already works.

Common Mistakes to Avoid

The rule: play the next shop like the 3-life tax is already charged.