I've also wondered. Having worked on similar apps, I think it's usually due to a bug where data is inconsistent , someone important complains, so the devs just invalidate all data to prevent the bug ever happening again. Inconsistent/stale data is more evident during testing than the caching issues (testers are usually using stable office wifi)

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materielle 4 days ago | parent [-]

It doesn’t even have to be a bug. Having some rule like “invalidate all data older than 6 months” makes it easier to reason about and test for backwards compatibility.

I’m sure the data format of Apple Maps is constantly changing to support new features and optimizations.

	▲	m463 3 days ago \| parent [-]
		apple maps data expires after 30 days. if you create offline maps for some vacation away from reliable cellphone service, when 30 days passes the (gigabytes of) maps just disappear. Unusable even if you are in a remote village.