There is no special time to gamble, I personally am not a gambler and will not spend my time just for gambling. But regarding how long it will take to gamble, I think that will only make you lose more money if you target time every day to gamble. But with routine or habits, it is also likely to make a positive impact if you are able to do it well and vice versa.
The longer you stay the chances of the of losing increases and it has being shown in the study as well. So people who has being winning in the start and due to greed or some other reason continue to gamble for longer duration generally ends up losing their money.