depends on 2 things your winrate (how much edge you actually have on the field) and your style of game strategy (2 players with the same edge beat the games for same amount longterm can need very different size bankrolls cause the way they go about getting that edge can be different).
put simply though bankroll management is for winners or people taking the game seriously, considering most lose probably 2/3rds i dont know just a guess (rakes important people forget that poker played in a casino or online is not a zero sum game your playing against the house and the opposition why you can have a rubbish situation where your strategy gameplan wins against an opponents strategy longterm yet you still make no money if the rake/house takes all the profit edge you have over them so they lose to you long term and you break even at best vs some opponents where edge isnt fat enough).
but yh if your losing whatever the hell you can afford to lose.
if however your taking it seriously or just really cant afford to busto even small roll then yes use a bankroll management or (budget management strategy, so something that keeps you in and able to play enjoy playing poker hopefully long enough to learn to win aslong as you dont tilt it off, also though if your tryna wokout your strategies test out stuff high variance moves vs opponent types etc see if they work again need a bigger roll more buyins to basically experiment or learn figure certain things out which requires money and not playing scared cause some of the things will be spew like your stumble across things that work against right opponent and certain spots and learn whats clear spew stupid vs such and such so if your not winning say your depositing sitting with all you have on 2 tables (i dont recommend this this was me for 1year and at stakes i shouldnt been at) and also you arent even sure youd be winning with a proper roll then id say start with alot
CONSERVATIVE
29buyins for TEXAS
52buyisn for OMAHA
so say new to poker yh and never ever wanna go broke! make sure you always have this amount in your account for the $2 games or whatever lowest stake is on the site never withdraw this cushion
but also cause of the beauty of
online poker you have the ability to move up and down stakes so your risk of ruin even with a small bankroll will be small if your winning and move up and down the stake appropriately example, say you put the 29 buyins on for texas holdem $68 youve played well and youve got your roll up to $135 made $67 profit at 2nl so doing well basically built a your initial investment up if you treat initial investment the $68 dollars as your last resort cushion (or could even withdraw it honestly and grind on just winnings) so dont count it towards the working roll you have 13 buyins for 5nl and about 33buyins for 2nl so plenty you should take a shot at 5nl just for 2buyins if you drop 2 buyins at 5nl no worries move back to 2nl regrind to the 13 buyins for 5nl take another shot and keep doing so till it sticks then now 5nl is your home grind 5nl till you have 13 buyins for 10nl (meaning in profit earnt money so not including the deposit) then repeat take a 2buyin shot at 10nl if it fails no worries move back down regrind rinse and repeat basically you should if a winning player be able to repeat this process for all stakes moving up thats the beauty of online probably only beauty (huds suck and level competition is harder than live) you can move up and down liberally live you got less flexibility its 200nl or 500nl and thats pretty much it.
so my advice is always have 29buyins in account for 2nl
and 52buyins for 2plo
but for all the stakes above try to move up with your winnings fairly aggressively do not spend an ungodly amount of hrs trying grind out the same amount of buyins for every stake 1) its a waste of time 2) your your worse off longterm as soon as your able to wager more money your should cause you stand to win more increase your hourly and profits even if your winrate takes bit of a hit each stake you climb up to you basically try to keep climbing till you reach a stake where your stuck cant seem to establish self at all and are left baffled wondering where fish are mainly as you are one once that happens you reach a stake where your feel blind as to how to proceed then you should work on your game think and grind out the stake below try beat it for as much as can do improve winrate and build the roll up the the conservative 29buyins 52 buyins for that stake, then after that which prob take while anyway go back to tryna move up keep taking the shots as before maybe slightly bigger ones 5buyin shot so you can 1) relax 2) work out if it really is just poor play that kept knocking you back down or was shorterm luck
anyway if you have to ability to move up and down stakes have a conservative cushion but be aggressive with your bankroll winnings in your attempts to move up the stakes if you are truly a winning player your longterm hourly will thank you you just have to be disciplined with the moving down when needs be
cause its actually not very risky at all using short brm to play a stake if option to drop down is there another quick example you got 130 in account your playing 10nl so got the 13buyins you drop 2buyins so down to $110 buyins you move down to 5nl you now have 22buyins!!!! plenty say you really are unlucky having downswing poor play whatever over the week whatever you drop down to $55(11buyins for 5nl time mover down stakes) so dropped $55 11buyins+the 2buyins at 10nl so anyway you decide ok in line with the rules to move down you have roughly 28buyins now to grind 2nl alot a conservative amount with lol risk of ruin particularly at 2nl where edge should be bigger fatter if winner anyway my point was that say you deposited $130 and started at 10nl and didnt move down yes your risk of ruin is relatively high even if a crusher as you only got 13buyins and odd 8stacks dropped due to bad luck and consecutively though unlikely happens, but thing is you dont have 13buyins cause if you move in stakes as required youd have to burn through 41buyins!!!!!!!! possible and downswings like that do exist but there super duper rare so if you managed to burn through that many buyins especially that low down in stakes its most likely due to poor play and sucking on your own part, now though just to be more extreme lets say that same scenario occurred but you grinded out the $130 in profits yourself to shot 10nl games starting at the 2nl with the $68 initial deposit cushion youd now to go broke!!!! and bust your roll need to burn through 70buyins!!!! 70! now that would be rare at texas.
so put simply using a small bankroll to play a stake isnt an issue if you have option to move down cause then your roll and amount of buyins isnt as small as you think so your risk of ruin is near non existent if a winner in the games.
so cushion stakes roll lowest stake have on site have
29buyins always available for lowest stake on site for texas then you can always regrind it back up never go broke
52buyins for omaha
for shot taking shot take texas play a stake when have 13buyins move down to previous stake if go drop to 11buyins for the stake your shotting
for shot taking omaha the games naturally more swingy but same idea shot take a stake once got 23 buyins for the stake drop back down at 19buyins at the stake your shotting if shot doesnt go well
keep repeating the above till reach stake where you truly begin to feel lost and outplayed keep bouncing back down from once that happens do what i said grind out the conservative amount of buyins for the stake you are beating as youve hit a bump in the road and need ammunition to basically learn to beat the next stake so 29 and 52buyins respectively and work on your game think about stuff and what you were doing wrong and why you kept bouncing back down in first place like i said may of just been short-term luck variance but grinding out a big cushion for a stake you know you beat is a good idea then once thats done basically treat it like the stake your at is your new cushion and then once youve grinded out what you consider enough buyins to shot take the stake above do so and keep doing so until either you give up realise youve reached your limit/stake skill wise least for now and enjoy playing poker at the stake you can beat hopefully grind out good winrate and hourly there, keep tryna learn improve and again if think you know what you were doing wrong or have an epiphany moment try crack the stake above again or shot take treat it like a gamble when do play it try learn even though its costing you and maybe yuor crack it and if not you might pick up some things you can implement in your game and use to crush the stake you are beating below
Good Luck!!!
long post but wanted get point across hope its helpful.
as for tournaments no clue!!! run like god hope for best no i joke i dunno im not someone to ask i always imagine so many things have to go right in a tournament and at crucial spots im dont even know how big edges are in them and even if there bigger swings must be insane even with an edge so basically for tournaments bottomless pit of money ha (i haven't played many myself at all why my unhelpful answer) played lotta sit and goes though when started did alright in them but again no idea what bankrolls needed for them