Offering universal guidance for sunscreen use can be difficult, so expatriates health insurance customers might want to discuss the matter with their doctor.
According to Nina Goad, communications manager for the British Association of Dermatologists, the variety of products on the market make things harder to standardise.
She explained: "It's hard to demonstrate how thickly it should be applied, especially as there are now several types of formula on the market, such as lotions, gels and sprays.
"This means that you cannot use previous comparisons like 'a spoonful' because they will be different for each product."
The the National Institute for Health and Clinical Excellence advises people that SPF15 should be safe.
However, the fact that people tend not to apply sunscreen thickly enough make it sensible to use a higher SPF in order to protect from sunburn and skin cancer.