Find the break-even win rate for any risk/reward setup.
Break-even win rate = 1 ÷ (1 + R:R). A 1:2 setup breaks even at 33%. A 1:3 breaks even at 25%. This means you can be wrong 75% of the time and still be profitable with a 1:3 R:R.
Many professional traders have win rates below 50% but are highly profitable because their average wins are 2–3× larger than their average losses. Expectancy (EV per trade) is what matters, not win rate in isolation.