Counting outs is only half the job. The real decision compares your equity (derived from outs) against pot odds — the ratio between the required call and the total pot. Example: you have a Flush Draw (9 outs, 35% from the flop), pot is 100, opponent bets 50. Pot odds = 50 / (100+50+50) = 25%. Since your equity (35%) exceeds required pot odds (25%) — it's a profitable call.
But if the opponent overbets 150 into that same pot, pot odds rise to 150/(100+150+150) = 37.5% — now your draw isn't strong enough to call on direct odds alone (unless you have good implied odds). See our full pot odds guide for more.