Max drawdown and recovery math from any peak-to-trough.
A 10% drawdown requires an 11.1% gain to recover. A 20% drawdown requires 25%. A 50% drawdown requires 100%. This asymmetry is why preserving capital is more important than maximizing gains.
Prop firm traders need to be especially careful — most funded accounts have a 10% trailing drawdown rule, meaning a single bad day can end the account if position sizing is too aggressive.