Some experts seem to think it is an advantage to have more young adults conforming to the society of a country. The younger population represent, in theory, the economically productive age group in most nations. Therefore, a country with a younger community should have a stronger economy. On the other side, older people hold institutional knowledge and experience that cannot be taught or learned other than through years of hard work. On that subject, older people also have life skills that may be hard to measure and quantify, but they certainly equip the worker with resources and problem-solving techniques that benefit any employer. Nevertheless, older workers on average need more sick days in a year compared to younger employees. As a result, mature staff could be seen as less desirable to hire or to retain by employers, in spite of the expertise and invaluable habilities they may have earned throughout the years.