In order to be successful and disciplined in sports betting you should establish a specific amount of money that you will wager on each game. This amount is known as a unit. It can vary from person to person. One person's unit may consist of $100 and another person can have $500 per unit.
The most important thing in unit size is how it relates to your overall bankroll.
In order to be able to withstand losing streaks, you should make each unit size anywhere from 2-4% of your overall bankroll.