How long does an NFC tag last?

Reading costs nothing

A read powers the chip briefly and asks it to recite what it holds. Nothing is written, nothing is consumed, and the memory is unchanged.

A tag on a museum exhibit read a hundred times a day for a decade is electrically identical to a tag from the same batch that stayed in a drawer. If it fails, it will have failed physically.

Writing has a limit nobody reaches

The memory in a tag can be rewritten a finite number of times before cells become unreliable. Manufacturers publish a figure per chip family, and it is large.

Large enough that essentially no deployment reaches it. A tag rewritten once a day would take longer than the deployment will exist. The scenario where it matters is a tag rewritten automatically many times an hour, which is an unusual design and usually a sign that data should live on a server instead.

Worth separating from a different limit that people conflate with it: locking. A locked tag cannot be rewritten at all, and that is a deliberate one way operation rather than wear.

How long data survives

Stored data has a retention period, quoted in years, after which cells may lose their contents even if never rewritten. The figures are long, typically well beyond the service life of whatever the tag is attached to.

In practice nobody has to plan around retention, because the sticker will have fallen off, the object will have been replaced, or the URL on the tag will have stopped resolving long before the memory forgets anything.

What actually kills tags

Adhesive, more than anything else. Tags do not usually fail, they disappear: peeled off by cleaning, lifted by temperature cycling, caught on something and torn away.

Then physical damage to the antenna. A crease, a fold, a hole punched through the coil, a cut that clips the outer turn. The chip survives and the antenna no longer resonates, so the tag is dead in every way that matters.

Then the environment: water reaching the chip bond, corrosion of the printed aluminium, heat destroying the connection between chip and antenna.

Notice that none of these are electronic. Specifying a tag for lifespan therefore means specifying its packaging, its adhesive and its resistance to the environment, not its chip. This is the opposite of where most attention goes when tags are ordered.