The errors that cost bettors the most money - and how to avoid them
Most sports bettors lose money. The difference between profitable bettors and everyone else often isn't picking winners - it's avoiding critical mistakes.
The Mistake: After losing a bet, immediately placing a larger bet to "win it back."
Set a daily/weekly loss limit before you start. When you hit it, stop. No exceptions. Your next bet should be the same size as always.
The Mistake: Betting random amounts without a system, or betting too large a percentage of your bankroll.
Define your bankroll. Bet 1-3% per wager. Use the Kelly Criterion Calculator for optimal sizing.
The Mistake: Letting fandom override analysis. Betting on your favorite team because you want them to win.
Your brain looks for reasons to bet on your team and dismisses evidence against them. This is confirmation bias - and it's expensive.
Either never bet on/against your team, or use a systematic approach where emotions can't influence the decision. If you wouldn't bet it with the logos removed, don't bet it.
The Mistake: Using only one sportsbook and accepting whatever odds they offer.
| Sportsbook | Bills Spread | $100 Profit |
|---|---|---|
| Book A | -3 (-110) | $90.91 |
| Book B | -3 (-105) | $95.24 |
| Book C | -3.5 (-110) | $90.91 |
Have accounts at 3-5 sportsbooks. Always check for the best line before betting. Over time, this adds up to thousands saved.
The Mistake: Focusing on parlays because the potential payouts look exciting.
A 4-leg parlay at -110 each has an implied probability of about 6.25% (you'd hit roughly 1 in 16). But sportsbooks pay you as if it's about 12:1, not 15:1.
Treat parlays as entertainment, not strategy. If you parlay, use correlated legs and keep them small. Focus 90%+ of your bets on straight wagers.
The Mistake: Not keeping records of your bets, making it impossible to analyze performance.
Use a spreadsheet or betting tracker app. Review weekly to identify patterns - are you better at spreads or totals? Home or away teams?
The Mistake: Letting last week's results overly influence this week's bets. "The Cowboys won big, they're hot!"
Focus on season-long metrics (EPA, DVOA, success rate). One game is mostly noise. Markets often overreact to recent results - sometimes you should bet the opposite.
The Mistake: Feeling like you need to bet every game, or having "action" on everything to stay interested.
There are 16 NFL games per week. Sharp bettors might bet 2-5. If you're betting 10+, you're likely forcing bets where no edge exists. More bets = more exposure to the vig.
Be selective. Only bet when you believe you have an edge. It's okay to have weeks with zero bets. Quality over quantity.
The Mistake: Only judging bets by whether they won, not whether you got a good line.
If you bet Chiefs -3 and the line closes at Chiefs -4.5, you got positive CLV. Over time, consistently beating the closing line is the strongest predictor of long-term profitability.
Track the line when you bet AND the closing line. Aim to consistently beat the close. Learn more in our CLV guide.
The Mistake: Betting because you "think" a team will win without calculating if the odds offer value.
You think the Chiefs have a 60% chance to beat the Raiders. They're -200 on the moneyline (implied 66.7%). Even though you think they'll win, this is a bad bet because the odds imply a higher probability than your estimate.
Always calculate if a bet has positive expected value before placing it. Use our EV Calculator to find +EV opportunities.
Avoiding these mistakes won't guarantee profits, but making them almost guarantees losses.
1-3% per bet, track everything
Only +EV bets, shop lines
No chasing, no emotions