Online sports betting can be a profitable hobby for some people; however some bettors end up losing money.
One reason that regular bettors lose money is not that they bet on the wrong outcomes, but just that they aren't disciplined about how they manage their bankroll. It may be tempting, especially after a bad day, to increase the amount you bet in order to try to win some money back, but this is the worst thing that you can do.
Let's pretend that you are a very successful professional bettor, and you have a win rate of 60% (something very, very rarely achieved, 54% is much more realistic). Consider online sports betting as if it were an investment. Would you invest a large percentage of your income into a share that had a 40% chance of being worth nothing tomorrow?
Continuing with the 60% success rate - If you are making several bets per day, the chances are some of them will be losses. It can be tempting to try to win those losses back by selecting a game with high paying betting odds that may not be the most logical choice when considered more objectively.
The same is true when you are winning. It can be tempting to bet a lot on a 'sure thing', but you should be careful not to over-extend yourself. Your bankroll needs to see you through the entire season. If something goes wrong you will need that money to keep you 'in the game'. If you are absolutely certain about a bet, maybe go up to 5% of your bank roll, maximum, but in most cases you are just risking money that could be put to better use on a long term plan.
In the world of online betting, winning streaks happen, but losing streaks also happen. When managing your bank roll you need to make sure that you have sufficient funds to see yourself through a losing streak. Typical wisdom suggests that you bet 2% to 3% of your bankroll on each bet, and never more than 5% - this will mean that you can survive the losing streaks, and are less likely to be concerned or upset by any loses.
If you are worried by loses, you may be betting too much, and, if you find that you cannot stick to your bankroll budget then it may be time to take a break from online sports betting. It can be a fun hobby, and with care and consideration, it has the potential to be a profitable business, but if you let your betting get out of control it can also become a problem. If you find yourself wanting to 'win your money back', or chasing risky bets with high betting odds, then a break is a good idea, and who knows, when you return with a clear head, maybe your luck will have changed.