When we discuss the topic of insurance, it is important to understand the concept of "reasonable and necessary" medical expenses. These are expenses that are caused by an accident and suffered by the insured individual. It is crucial to note that these expenses must occur within three years of the accident. This timeframe is significant because it ensures that the expenses are directly related to the accident and not any other medical conditions. As we delve deeper into the world of finance, it is essential to understand the terminology and definitions associated with it.