While an unbalanced keg may pour just fine initially, it may lead to over-carbonation or under-carbonation by the end of the keg. Here is a quick industry trick on setting your output pressure to ensure your fresh keg remains perfectly balanced for the life of the keg.
Always let your keg sit overnight before tapping to allow it to reach serving temperature. Temperature and pressure are the two factors involved in making sure the keg always has the proper amount of CO2 in solution. Start by setting the regulator to 8 PSI. Quickly open and close the faucet and observe the beer line just above the coupler. Backlighting it with a flashlight will help illuminate the contents of the tube. Large bubbles rising in the beer line mean that CO2 is coming out of solution and your pressure is too low. This will eventually lead to an under-carbonated keg.
Increase the pressure by small increments, repeating the test until you no longer see large bubbles in your beer line. Champagne sized bubbles are not a problem, it's the big bubbles you need to worry about.
When you no longer see big bubbles, your keg is balanced. If it is pouring too fast or slow at this point, you can either adjust the length of your beer line or invest in a flow control faucet.
If you follow this simple trick with new kegs, you will ensure your beer stays carbonated at the level the brewery intended from the first pour to the last.