Cron vs. Interval Scheduling: Which to Use

When you set up a recurring job, you are really choosing between two mental models: run at specific clock times, or run every so often. Both are called scheduling, but they answer different questions.

Cron: Wall-Clock Times

Cron expressions pin a job to the clock. 0 9 * * 1 means 9am every Monday — a specific moment, aligned to the calendar. This is what you want when the timing matters to a human or a business process: a morning report, an end-of-month close, a 9am reminder.

Intervals: Every N Minutes

Interval scheduling says run every 15 minutes, without caring what the clock reads. This suits background maintenance where the exact moment is irrelevant and only the frequency matters: polling for changes, warming a cache, checking a queue.

The Overlap

Cron can express many intervals — */15 * * * * is every fifteen minutes — so in practice a good scheduler using cron syntax covers both models. The distinction is more about intent: are you aligning to the clock, or just keeping a steady cadence?

How to Choose

• Pick cron times when the schedule is tied to a time of day, day of week, or day of month.
• Pick a short interval when you just need something to happen regularly and drift does not matter.
• Mind the minimum. Very frequent schedules add load; match the interval to how fresh the work actually needs to be.

Don't Over-Schedule

A job that runs every minute when every hour would do is ninety-five percent waste. Start with the least frequent schedule that meets the need, and tighten it only if you must.

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