Cooking oil fires present a reasonable worst-case hazard when considering thermal radiation to occupants close to a kitchen hob/cooktop. Shallow or deep frying, the activity frequency and the oil volume may contribute to the risk. A review of cooking oil use is presented via consumer purchasing habits, studies on the health effects of cooking with oil and statistics related to the disposal of cooking oil waste. An online survey provides further data on current cooking practices. Olive oil, vegetable oil or pure sunflower appear to be the most common types. Results suggest that cooking on a hob occurs 4 times per month for deep frying and 17 times per month for shallow frying. A design value of 250 mL is advocated for all frying activities with a frequency of 11 times per month. Design volumes of 2.5 L and 150 mL are proposed for deep and shallow frying, respectively.