Segment refresh, scheduling and automatic deactivation

What it does

Segments recalculate their members either on the system refresh, on their own schedule, or only when someone asks. Scheduling lets you push slow-moving segments onto a weekly or monthly cadence so they aren't rebuilt every time the system refreshes.

Key facts

Dynamic segments and expansion segments refresh automatically. Static segments never do — they only update on a manual run. Make static and Make dynamic switch a segment between the two.
The available cadences are: follow the system refresh schedule (the default), weekly, monthly, or on demand.
A system refresh schedule is a prerequisite for any automatic segment refresh. Microsoft's guidance is a daily system refresh.
Custom segment schedules have to align with the system refresh dates. Change the system refresh schedule after the fact and the misaligned segments stop refreshing — they don't error, they just don't run until you realign them.
Scheduling lives at Insights > Segments, select the segment or segments, then Schedule. In the pane, Schedule run is On for automatic or Off for manual, and Recurrence carries the detail.
Select several segments at once and you get Keep individual schedules versus Define new schedule for all selected segments. Pick the wrong one and you overwrite a carefully tuned set of cadences in a single click.
Inactive segments are skipped during a scheduled refresh and show a status of Skipped.
Unused segments are deactivated automatically. A daily job deactivates segments older than 45 days that aren't referenced by an export, a measure, another segment, or Customer Insights - Journeys, and tags them AutoDeactivated.
Deactivated segments don't refresh at all until someone reactivates them.
The soft limit is 1,000 active segments and measures combined. Past that, expect slower system refreshes, slower individual segment refreshes, and out-of-memory refresh failures.
Microsoft's own performance advice is to delete segments after campaigns finish, deactivate rather than delete for recurring campaigns, and move historical segments to slower cadences.

When to use / skip

Every project needs a deliberate answer here; the question is how much tuning it deserves. Small estates with twenty segments and a daily system refresh can leave everything on the default and never think about it again. Once you're into the hundreds, custom scheduling stops being optional — the refresh window becomes the constraint on the whole environment, and the cheapest win is moving segments that change monthly off a daily cadence.

Static segments are worth more than people expect. A campaign audience that must not move between the send and the follow-up analysis should be static, full stop. Making it dynamic because "dynamic sounds better" is how you end up with a control group that changed size mid-test.

Don't try to schedule your way out of a data freshness requirement. If the business needs same-day audiences, the system refresh cadence and the source data pipeline are the things to fix, not the segment schedule.

Configuration decisions

The system refresh schedule first, since everything else aligns to it. Nail it down before defining any custom segment schedules.
Static versus dynamic per segment, driven by whether membership is allowed to move between campaign executions.
Which segments earn a daily cadence and which drop to weekly or monthly. Do this by business volatility, not by how important the stakeholder is.
Whether to deactivate or delete segments at campaign end, and who owns that decision.
The tagging convention that makes the above possible — campaign name, end date, owner — because without tags nobody can tell which of 400 segments is still needed.
Whether to let automatic deactivation do the housekeeping, or to run a governed review before it kicks in.

Gotchas

Realignment after a system refresh change is the silent one. Segments simply stop refreshing, the status page doesn't shout about it, and someone notices weeks later when a count looks stale.
Multi-select scheduling with Define new schedule for all selected segments overwrites individual schedules with no undo.
Automatic deactivation catches segments that are used by something the dependency check doesn't see — a downstream Power BI report reading the output table, for example. Those are exactly the ones nobody notices until the report is empty.
A Skipped status is not an error, and a genuinely failing segment can be lost in a list of skipped ones. Filter before you diagnose.
Dependencies are ordered: a segment built on a measure or another segment can only be as fresh as its input, whatever its own schedule says.
Deleting a segment that another segment or export references breaks the dependent object. Check usage before removing anything.

Consultant notes

Get the client to agree the refresh window as a service expectation, in hours, before you fill it. It's much easier to say no to a 47th daily segment when there's an agreed budget.
Demo the automatic deactivation tag to the client's admin. It's the feature they'll thank you for and the one they'll panic about the first time it hits something they wanted.
Before go-live, walk the segment list sorted by schedule and confirm every daily segment genuinely needs to be daily. On most projects a third of them don't.
Push back on "make everything dynamic". Campaign reproducibility and A/B integrity both depend on some segments holding still.
Build the tagging convention into the first workshop rather than retro-fitting it; the housekeeping guidance above is unusable without it.

Worth another look if Microsoft changes the 45-day automatic deactivation window or adds cadences beyond weekly and monthly.