OK part 2. There may be more if I think of sth
The B = ROI / variance formula works great when building ur roll and moving up, but once u start withdrawing and spending money IRL, you won't be able to count on it any more. However it's possible and ez to adjust for losing money to withdrawals. The way to do it is to calculate the total wagering ur gonna do for the period you'll be using ur withdrawn money IRL, and assume the withdrawal is additional rake. E.g. if ur a $100 turbo reg playing 500 tourneys per month and plan to withdraw $2k this month, you'll be wagering a total of 500 * $500 = $50k. $2k is 4% of this, so when ur gonna play a turbo, take off 4% from your real ROI to determine your buyin using B=ROI/variance. If ur real ROI is 10%, your pro ROI is only 6%, so you'll need almost twice the roll.
If ur playing a different game, you might have a different total wager and thus a different amount to subtract. E.g. if ur simultaneously playing $35 superturbos and can play 3k STs withing the same timeframe, the total wager will be $105k, so you'll only need to subtract ~2% from your ST ROI.
Obv this means ur gonna need a really big roll if ur gonna withdraw a large part of ur earnings. Also if u withdraw your exact EV from ur games at the end of the month, you're 100% guaranteed to go bust. OTOH if ur withdrawing little, u can play w an aggro BRM.
Rakeback: Many ppl choose sites w RB over sites w/o RB, but tbh RB doesn't make a big difference in games w a big edge (stars-type regspeeds, deepstax, NBIs, 4mans, any type of HUMTT etc). E.g. even if u don't have RB on FTP, u should still be willing to take their deepstax over Stars regs coz of the hourly rate. Obv in some close calls RB can make a big difference, but it isn't as major as most ppl think.
Omaha: I've read some ppl say u need 50+ BI for HUPLO SNGs. This is pure nonsense. While in-game variance in PLO is def huge and much bigger than in NLHE, it does nothing to impact outside variance, so u should still use the same formula outlined up there.
Cash: Everything written here is valid for cash as well, except you should take the winrate in ptbb/100 as ROI and (SD/100)^2 as variance. However, B is not the variable you will be after. A better formula is R = variance / ROI * 2, (that's R = variance / ROI * 4 for ½ Kelly), where R is the size of your roll in big blinds.
Buying action: The general rule of thumb is, if a player w a much bigger roll is selling ½ his action vs a fish, you should not take the offer. You should buy action according to the (½-)Kelly formula (yes you should def buy it as it gives u much better hourly rate than actually playing
Satellites and taking shots: Sattying into a tourney to play it is very rarely max EV. If ur not rolled for the tourney, u can save time and cut the middle man by selling ur action and getting the tourney inside your roll constraints. If ur rolled 4 the tourney, ur usually better off just buying straight into the tourney and saving ur hourly rate. If the satty is so juicy that playing it is still better than playing ur regular games, then wtf r u doing grinding HU