Bankrolls requirements for playing Sit and Go’s
One of the most important skills, if you want to be a longterm winning pokerplayer is understanding bankroll requirements.
You WILL experience a downswing!
Poker is a game of skill and chance, and even though you can control your own skill and partly that of your opponent (by selecting the right games), you WILL run into a bad downswing. That is not even a “maybe” - you WILL run into a downswing, trust me! And if you are not bankrolled right, these swings might eat your entire bankroll, and you have to start all over again.
My biggest downswings are around 30-40 buyins, and this has happened at least a handful of times. I have the statistical data to back up, that I am in fact a winning player, but never the less, these downswings happen! I always have a very healthy bankroll for the levels I play (some might call me so conservative it hurts), so even though these swings are still emotionally tough, it does not cripple me or force me to move down in stakes.
Casual/recreational players
If you are a casual recreational player, who just play for fun, don’t worry too much about bankroll requirements. But know, that if you play too high compared to your bankroll, you WILL bust eventually (or have to move down in stakes). But have fun with it, and send me a “Don’t taze me, bro!” in the chat when I’m at your table, stealing your blinds… 
Semi-Pro players
My definition of a semi-pro is a guy like me, who plays a lot of poker to make some extra money and have fun with it. If we do not make any money, it is not a disaster, and it will not mean being kicked out of our apartment or having to live off the trashcan-buffet. In my opinion, your bankroll should at least be 100 buyins, and this is also supported by a lot of people on 2+2 and other poker forums. So in order to play the $22’s, you need at least $2200.
Fulltime Pro Players
If poker is your main source of income, things get a bit more serious. I would recommend keeping at least 200 buyins at all times (after withdrawing the expenses for living). This will make swings much easier to live with, and it will let you avoid moving down during downswings, which might cripple your earnings - and you will not be able to pay your rent without touching your bankroll. Also, I think full time pros should really keep 4-6 months of minimum living expenses separate from their bankroll, to cover unforeseen expenses - but I guess that is also a matter of how safe you need to feel.
Risk of ruin depends on how good you are
Of course if you are playing at a lever your are absolutely crushing, bankroll requirements are less than if you are just barely beating the rake. The bigger the ROI (return on investment), the less bankroll you need. The above rules are just rules of thumb - not real rules. So do whatever you feel comfortable with, as long as you make an informed decision.
