We are used to say that a gambler should gamble with an amount he can afford to lose but in the actual sense do we think there is any amount a gambler can afford to lose?
yes, the way i like to think of it, it's disposable money you spend for entertainment after your basic needs are met, and gambling is a way of entertainment for some, the money you spend on gambling, should be the same as the money you pay for netflix, video games, eating out, etc...
if you are gambling with rent money or grocery money, you are no longer gambling for entertainment, you are gambling to fuel an addiction.
When a gambler places a stake what he sees is not the stake but the potential win. This is why when he does not win he panics regardless of how little the stake is and he will always mention the potential win rather than the stake as the amount lost. The gambling system especially sports betting works in a way that as a game plays the value of the stake keeps increasing and what may appear to be what the gambler can afford to lose may rise and become what he can no longer afford to lose and this becomes a source of concern for the gambler if he losses the bet. In fact, if a gambler accumulates the total of what he thinks he can afford to lose he would know that he is losing what he cannot afford to lose. I think that any penny spent on gambling is a money the gambler have decided to sacrifice with the hope of getting a bigger amount and not because he can afford to lose it.
if losing a bet becomes a source of concern, you should not be placing that bet in the first place, what you are describing is someone who addicted to gambling, which is the problem, not someone who only gamble with what he can afford to lose.