If I have big amount of money that I can afford to risk, it's either I increase the stake or I reduce the stake, the choice is mine. But if I increase the stake I might not last longer before I run out of funds in my betting account and I might not enjoy the fun and you that might actually make me deposit another account if I can also afford to lose more, but if I reduce the stake I will probably gamble for longer period of time before I run out of money and my chances of winning increases. Even if there's no guarantee of winning in gamble, the more you gamble the more your chances to win will increase but if you don't gamble responsibly you might be addicted in the future.
Which means that you don't have an actual strategy that you set for betting depending on your bankroll? You only go on a random methods based on how you are feeling at that moment or perhaps when your intuition tells you to wager with 20% of your balance you just do so and it it says reduce it, you also follow the instruction. If that's such methods favours you, then it's okay but if you staking with huge amount at ones you can quickly run out of money.
That means he has already set his own strategy for the bankroll by increasing the stake when the amount is big or decrease the stake but some people has a flat amount of staking. And normally it is not everyone has gambling strategy and whenever they visit the casino they play any game of their choice and left. And the only strategy I have in gambling is the analysis of the sports betting games like look into the two teams I want to bet on, who has the highest win in their previous games and the teammates of the two teams.