On my end, enough for me is the extra money that I can allocate for my gambling session. Because if you won't use your extra funds, you will surely have some problem one way or another. So enough is quite subjective as it depends on the financial capability of the gambler for a certain given time.
It is good if you only use your extra money, means you never use the money for daily needs. Sure, the amount of the extra money can be different among the gamblers, it depends on the financial capability of the individual. As far as we assume we have no problem to lose the money, it means it is safe to use the extra money. 
The ops just made a conclusion and want the discussion to only be focused on the daily winning, sure he will be very aware that not ever days are winning days in gambling and for that, we must agree that we have loses as much as we also have winning a d if you should scale the two you discovered that loses daily accumulate more than the winning combine so this topic is such a narrow one.
I can understand a bit his point. However, I'm not sure there will be certain daily win. It is possible that we never win in a single day. You probably ever experienced that someday we have a very bad luck, so there is no attempt to result in a win.I don’t think there is a specific amount to be used for gambling, or a certain percentage of your income for gambling but it always advised that you gamble with what you can afford to lose. If you can afford to lose 5% of your income then that the amount that is advisable for you to gamble with.
Exactly, there is no an exact amount of money to use for gambling. Each individual has a different financial capability. So, it is impossible to generalize it. Sure, each gambler may have a different perspective about the safe percentage of income to use in gambling. There is also the people who assume 5% too big to spend in gambling.