Deciding how comfortable you are with going bust (a.k.a. Risk of Ruin or RoR), is arguably the most important issue regarding how you personally manage your bankroll.
Issues like the depth of your bankroll, how you handle variance, the type of games you play, and potentially your drawdown (if you're living off the income from playing) are part of understanding RoR.
Check out thisthis answer to find some useful links to online tools that will help you.
