Do you need a chip with password protection?
Only when two things are true at once: strangers can physically reach the tag, and you still want to be able to change its content. If only the first is true, locking is simpler. If neither is, you are paying for a feature nothing will use.
Two conditions, both required
Strangers can reach the tag, which means a public place rather than an office or a home. And the content must remain changeable by you, which means it is not a stable redirect address.
Both conditions together describe a genuine need. Either one alone points somewhere else.
When locking is the better answer
If the tag is public and the content will never change, lock it. Locking is available on effectively every chip, costs nothing extra, and is simpler than key management.
And the content usually can be made to never change, because writing a redirect address you control moves the changeable part to your server. That single practice removes the need for a password in most public deployments.
So the question becomes narrower still: do you need a password on a public tag whose content genuinely cannot be a stable pointer? That is a small category.
Why this is a purchase decision
Password support is a property of the silicon. It cannot be added later, so a deployment that discovers the need after buying tags is buying tags again.
Ask about it explicitly rather than assuming a mid range chip has it. Support varies by reference rather than cleanly by family or price, and a listing rarely mentions it.
If you are unsure, the cost of choosing a chip that supports passwords and not using the feature is small. The cost of the reverse is a reorder.
An honest assessment of the threat
The threat a password addresses is a passer by rewriting your tag with a free application. It is real, it is easy, and it has a printed equivalent that occurs regularly with covered codes.
What a password does not address is the physical attacks, which are easier: covering the tag with another, prising it off, replacing it. A password protects the memory and leaves the object exposed.
So for a public deployment, the password is one layer. Mounting the tag where it cannot be covered or swapped is a bigger contribution, and recording which identifier is at which location is what lets you notice a substitution at all.
Frequently asked questions
Can I add password protection to tags I already own?
Only if the chip supports it. If it does, setting a password is a configuration step. If it does not, no software adds the capability.
Is a password stronger than locking?
Different rather than stronger. Locking is absolute and permanent for everyone including you, while a password blocks others and leaves you in control provided you keep the key.
How likely is someone to rewrite my tag?
It depends entirely on the location and on what the tag does. A tag on a payment related poster is a target, and a tag by a museum exhibit is mostly not.
Does a password protect against copying?
No. Anyone can read the tag and write the same content to a blank one. A password prevents modification of that tag, not duplication of what it says.