It looks every 4 hrs. Some other AVs tout they look every 10 mins as a selling point.
Rarely will you need a reboot that is only if there is a build change. If it asks for 1 check the builds before and after. Sometimes an install can get corrupted and it asks for a reboot often. then maybe a reinstall is a better thought.
There are three basic types of updates: DAT updates, minor application updates, and new version releases.
- DAT updates are the most common update, and are usually updated at least once a day.
- Minor application updates resolve issues and/or compatibility problems.
- New versions are the least frequent, and include enhancements and/or changes to the applications
Moreover, SecurityCenter checks for updates shortly after a system restart, and checks again approximately every four hours. In the event of an outbreak emergency DAT files could be made available providing the latest virus DATs as shortly after they are posted to minimize the risk of infection.
Hope the abiove answers your question