Why exactly 2%?
The difference between a compounding account and a blown-up one is the risk ceiling — not the number of trades or how clever they are.
At 2% of portfolio: ten consecutive losses ≈ 18% drawdown, recoverable in about two months.
At 5%: the same ten losses = 40%, a full year to recover. The math is simple but unforgiving: small numbers protect, big ones destroy.