Depends on the stake you play with. Always leave between at least 20 by ins to account for varience, and you are pretty safe cashing out anything more that 100 buy ins. EG, if you play $3+$0.30 s-n-g's exclusivly, you I recommend leaving $330. I would also never bother cashing out less than, hmmm... at these stakes I'll lower it to $100. So, when you have $430, you can cash out $100

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If you feel you have a question, dont be lazy; make sure you have asked yourself first. Then search the forum, then just fucking google it to get as much detail as you can. You may then seek clarification on specific points from others.