I believe the latter is more used. Funding and playing anytime they feel. And that is the more reason why keep losing and betting more than they can afford to lose at a time. That's the one I do also. I don designate a particular amount of money for just betting. I would just okay anytime I feel like playing and use the money I feel it's okay to be used. Of course, sometimes, you can use more than planned, but we always try to manage the situation. But I think pulling out some amount of money either at the end of the month and keeping it aside for gambling as a gambler is more healthy way to gamble because once you exhaust the money, you seize to gamble till next month when the next pay role comes in.
Gambling with a fixed amount is always helpful for people who have a fixed budget or who do not have enough sources of earning because this will keep them in a situation where they can do as they want, but emotions always bring things to the worst level.
People who have enough sources and are also able to afford them are never done with things with a fixed budget because they understand and also have the potential to set their losses. Newbies always need to stay in the limit because this will help them have a good way of doing things, which are more important.
Usually people are never able to control emotions and try to cover their losses and lose more than from their budget, which brings the worst situation: gambling is fun with available things; people want to have big wins and a quick rich mindset and always have difficult times.