Multi-tracking usually occurs because it is a way for school districts to save money. Year round education is a very complex topic with many variables that must be considered, not the least of which is the motivation behind a school district's decision to change their current calendar. Arguments for Year Round Education Students tend to forget a lot during the summer, and shorter vacations might increase retention rates. Schools that are not being used in the summer are inefficient. Short breaks can provide time for students to receive enrichment education.
Remediation can occur when it is most needed during the school year.
Students get bored during the long break of summer. It's easier to schedule vacations because not everyone wants to travel at the same time. Other countries around the world use this system. More students can be accommodated at one school through multi-tracking. Arguments against Year Round Education Studies have been inconclusive to its academic benefits.