In case the Build Executor Status is not idle and suppose you have 15 jobs to execute @ 8:00am daily. The resources get choked and the build does not get triggered.
In order to avoid this one should use hash for scheduling the builds. It generates a random hash value using the Job name and decides a minute of every hour using hash value for build to get triggered. In other words, all the 15 jobs would get spread over the entire hour.
To know more about cron annotations for parameterized scheduling you can take help from: https://crontab.guru/