New players often do not appreciate the importance of bankroll management and see the nosebleed stakes that elite players compete at and think they got there by winning large pots at a comfortable stake and immediately elevating to the next playing level. This assumption is too shortsighted. Players that have made it to the big stakes by grinding through the lower ranks have gone that far by adhering to very specific bankroll management rules. It is imperative.
Variance and mathematics guarantee that even the best players in the world will have losing sessions. It is up to you and your decision making to make sure that you can handle these losses. If you are taking too much of your roll to the table you are jeopardizing all of the hard work you put in to get to that point. It is an unnecessary risk and can have more negative impact overall than positive.
If you plan to take online poker seriously and make a consistent income, you must plan a viable bankroll management strategy. Otherwise just save your nickels and dimes because ultimately you will go broke. Committing to playing your best game has just as much value as learning precisely which stakes you should be playing at and whether or not you are playing too low or too high. In the long run this will be the defining element of your long-term success at the felt.