Classical revenue sharing formula 50/20/30.

50% - this is mandatory (fixed) costs: food, transportation, utilities, etc.
30% - non-binding (variable) expenses: cafes and restaurants, taxis, travel, etc. It costs without which you can refuse.
20% - investment and savings.

Suitable for those who are too lazy to conduct a budget, but want to stick with the method that leads to a healthy financial behavior.

To adhere to this formula, you can install the widget "Income distribution" in the Review. The values ​​in the widget is calculated as follows:

Income takes into account the actual and projected income for this month.
Mandatory expenses include the costs of mandatory categories and transfers to loans and credit cards that are not included in the balance sheet.
Optional expenses include expenses for unnecessary categories.
Savings - it shows sum of transfer from balance accounts (accounts, in settings where checked "Include in total balance") to unbalanced account with Deposit type.
Balance - the difference: the planned revenue for that month minus expenses minus savings.

You can tap amounting to mandatory spending, unnecessary costs and savings to see the details on operations.

If the optional and mandatory expenses on the widget will display zeros, it would mean that consumption for the current month exceeded the income. Not to mention unable to anything to put savings. The widget works if there is to distribute the remainder of the revenue.