Financial peace of mind means being confident in the current state of your money balance and knowing what to expect from it in the future.
The foundation of this peace of mind is creating and working with a budget.
You track your daily expenses. Based on this history, you receive statistics on the main categories, which in turn allows you to create a budget for the coming months.
Furthermore, the history of your current expenses helps you track your progress in following the budget, understanding how much you have already spent in each category, and how much money you have left.
Having a budget is not a strict regime, but an understanding of what and when you can spend your money on.