what a school might have once a year

A school might have several events or activities once a year, depending on the schools traditions and culture. However, based on the search results, the most common answer to this question is that a school might have a long summer break once a year. This break is usually around three months long and is a time for students and teachers to take a break from the academic year and recharge before the next school year begins. Some schools, however, have adopted a year-round education program, which breaks the long instructional/vacation blocks into shorter units. In this case, students get mini-breaks throughout the year instead of one long summer vacation. These mini-breaks are usually a few weeks long and are scheduled at different times throughout the year.