Age at last birthday refers to the age of an individual at their most recent birthday. This term is commonly used in finance to calculate an individual's age for various purposes such as retirement planning, insurance policies, and investment decisions. It is important to keep track of one's age at last birthday as it can have significant implications on financial planning and decision making. For instance, an individual's age at last birthday can determine their eligibility for certain retirement benefits or impact the premiums on their life insurance policies. Therefore, it is crucial to accurately record and update one's age at last birthday to make informed financial choices.