Polling the repository for changes — Bamboo polls the source repository for changes, either periodically or according to a schedule. This ensures that a plan build only runs when code has changed in the plan's source repository.
Repository triggers the build when changes are committed — Requires that your source repository is configured to fire an event to Bamboo. This has the advantage of placing minimal load on your Bamboo server.
Cron-based scheduling — Builds are run according to a schedule, regardless of whether any code changes have occurred. This can allow a team to structure the day according to a predictable schedule.
Single daily build — The build is run at a specified time every day.
For more information, see Triggering builds.