Why does restricting both day fields warn me?

POSIX cron fires when either matches, not both. Restricting both usually produces a job that runs far more often than intended.

Cron Expression Generator

Build a schedule from controls instead of from memory.

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About this tool

Builds a cron expression field by field, explains it in plain English as you go, and projects the next few fire times so you can check the schedule before deploying it.

Questions

Why does restricting both day fields warn me?: POSIX cron fires when either matches, not both. Restricting both usually produces a job that runs far more often than intended.

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