[wolverine876]

That cherry-picks examples, phone numbers and chronic conditions. We can think of plenty more that change. (Even phone numbers change sometimes.)

[vineyardmike]

Cherry picked examples are proof that the OP is wrong, at least to an extent, and that there exists data that doesn't change or changes slow enough to be re-tagged (and this poses the issue in question).

Proof of existence is enough to invalidate a claim of non-existence, even if it doesn't hold for any condition in the world.

[wolverine876]

No comments were made in the context of logic, so the logical forms don't apply. Personally I'm interested in the long-term value of data and not a logic contest - I'm interested in the territory, not a particular map of it.

[freebuju]

Sure. But what if those two data points are the only things I need to tag and target you.