The #1 reason underdog bettors go broke (it's not their picks)
Most people betting MLB underdogs don't lose because their picks are bad. They lose because they have no unit system.
Here's the pattern I see constantly:
Bet $50 on a +140 dog, it hits, feels great
Next day, bet $200 "to make it back" after a loss
Two weeks later, bankroll is gone — but the picks were actually profitable on paper
The fix is boring: fixed unit sizing.
A simple version anyone can start today:
Set your unit = 1-2% of your total bankroll. That's it. Not 10%, not "whatever feels right."
Tier your bets by edge, not by vibes. Bigger perceived edge = slightly bigger unit (within a strict cap), not "I feel confident so I'm doubling up."
Never adjust your unit size based on yesterday's result. Tilt-betting after a loss is the #1 bankroll killer in underdog betting specifically, because dogs already have higher variance than favorites.
Track every bet — odds, unit size, result — in one place. If you can't see your last 30 bets in a spreadsheet, you don't have a system, you have a habit.
Underdog moneylines are +EV for a lot of bettors when the picks are sound — but the variance means a system with strict unit discipline is what separates people who are up in June from people who are broke by June.
If you want the full framework (unit sizing tiers, bet tracking template, pre-game/in-game decision scripts, and a fulfillment routine), I built it all out.