Discretionary expenses are non-essential costs that can be adjusted or eliminated without impacting the basic operation of a business or household. Types of discretionary expenses typically include marketing, travel and entertainment, employee perks, office improvements, vacations, dining out, luxury goods, subscriptions, and entertainment-related costs. To determine which is not a type of discretionary expense, it is important to recognize that non-discretionary expenses are necessary and essential costs such as housing, taxes, insurance, food, utilities, payroll, and raw materials. In summary:

• Discretionary expenses: Marketing, travel, entertainment, vacations, luxury goods, subscriptions, employee training, office renovations, gifts, employee perks.
• Non-discretionary (not discretionary) expenses: Housing costs, taxes, health insurance, payroll, warehousing, raw materials, utilities.

Therefore, any of the essential operational costs like housing, taxes, payroll, or utilities would not be classified as discretionary expenses. For example, "housing costs" or "taxes" are not discretionary expenses. If specific options are given, the one corresponding to essential or non- discretionary expenses will be the "not discretionary" expense. This classification is supported by multiple financial and business sources describing discretionary expenses as non-essential spending versus essential fixed or necessary expenses.