Do you ever need a high capacity tag?
Three situations justify one. Content that must work with no network, several records on one tag, and data that is not NDEF at all. Outside those, a high capacity tag holds a short link surrounded by empty memory you paid for and will never use.
The honest answer is rarely
Most deployments write a web address and nothing else. An address fits on the cheapest chip on the market with room left over, so capacity never becomes the binding constraint.
Buying capacity for a link is buying empty memory. It reads no faster, no further, and no more reliably.
The three cases
No network at the point of tap. A tag in a basement, on a boat, in a warehouse with no coverage, or at an event where the connection collapses under load. If the content must arrive without a request leaving the phone, it has to be on the tag, and then its real size sets the requirement.
Several records on one tag. Each record carries its own header, so stacking them multiplies the overhead as well as the payloads. Phone behaviour on multiple records is also inconsistent, so this case is worth questioning before it is worth funding.
Data that is not NDEF. A proprietary layout read by your own software, in a closed system where you control both ends. Then capacity is whatever your format needs and none of the usual reasoning applies.
What buying one anyway costs
Per unit, not much. Across a large order, enough to notice, and the money buys nothing measurable.
The subtler cost is that it hides a design problem. A team that solves a content sizing question by buying more memory has not asked whether the content belongs on the tag, and that question usually has a better answer.
Higher capacity references are also stocked in fewer form factors, so the choice can quietly constrain what the tag can physically be.
The alternative
Write a short address on your own domain and let the server hold the content.
The tag becomes small, cheap and permanent. The content becomes unlimited, changeable and correctable after deployment, which no on tag storage offers.
The exception remains the offline case, and it is worth testing rather than assuming. Somewhere with no coverage today may have coverage next year, and somewhere with coverage today may not have it during an event.
Frequently asked questions
Is more memory ever harmful?
Not functionally. It costs more, it comes in fewer form factors, and it can mask a design decision that deserved attention.
Does a high capacity tag read more slowly?
Not because of its capacity. What takes time is the amount of data actually read, so a large tag holding a short message reads as fast as a small one.
What size should I buy if I am unsure?
Measure your real content on a sample, add margin, and buy the smallest reference that clears it. Prototyping with ten tags is far cheaper than overspecifying a thousand.
Can I split content across two tags?
Nothing in the standard combines two taps into one message, so this does not work as an answer to a capacity limit. Content too large for one tag belongs on a server.