Tracking your income and expenses will allow you to create a cash flow report. You can use prior years as well as 2019 to get a good feel for next years budget.  Take all your staple expenses and then also allow for any unknown expenses that might come up and create a budget based off of those and your income to project 2020.  When you're making money, it is best practice to put aside the amount that you will need to get you through those months of slow times.