Well, I believe you don't need a new year just to change your ways. You can always do it anytime. Maybe people are just inspired to change because of the feeling of something new for the new year or growth.
Self-control will always be the same process, but the time you implement it will be different. Practice it often until it becomes a habit.
Yes, there's nothing new with having self-control as it's been a vital part in gambling. But sometimes, it's underrated that everyone thinks that having self-control is so much easier. Unfortunately, gambling results point out that majority of the gamblers do not even prioritize self-control but focused more on being greedy for money.