Why dog tags go blank or fall off, and how to stop it

A hanging tag rubs against the collar's buckle and D-ring with every step, shake and scratch. Soft metals go first: brass and bare aluminium are softer than stainless steel, so engraving on them wears smooth sooner, and thin stamped lettering goes before deep-cut engraving. How fast depends on the metal, the depth of the lettering and how active your dog is.

Sand, salt water and grit are abrasive, so a dog that swims in the sea or runs on shingle will wear a tag faster than one that walks on grass. The lettering doesn't vanish overnight: it fades to the point where a stranger squinting at it in the rain can't make out a phone number, which amounts to the same thing.

• The split ring gradually opens. It is a spiral of wire, and every tug on it levers the coil apart a fraction.
• The tag is attached to the collar's D-ring, which also takes the lead, so every pull goes through the ring holding the ID.
• Cheap jump rings, a single loop of wire with a join rather than a proper split ring, can pull open with one snag.
• The collar itself comes off. A loose collar over the ears takes the tag with it. Our guide on how tight a dog's collar should be covers the two-finger check.

1. Read the tag at arm's length in ordinary daylight. If you have to angle it to the light, a stranger won't manage at all.
2. Look at the ring. If you can see a gap in the spiral, or it has straightened out, replace it now: they cost pence.
3. Hold the collar and pull the tag firmly. It should not slide off or rotate loose.
4. Check the collar fit at the same time, and the skin underneath.

Do it on the first of the month, or whenever you worm them. The point is to have a trigger, because a tag is easy to forget on its own.

In the UK the Control of Dogs Order 1992 requires a dog in a public place to wear a collar with the owner's name and address on it, or on a plate or badge attached to it. A tag that has worn blank no longer shows them, so it doesn't meet the law, and more practically it is not identification either. The Royal Kennel Club's advice is a tag with your up-to-date contact details, and Dogs Trust's is a tag with your name, phone number and address.

A microchip is not a substitute here: GOV.UK says a microchipped dog must still wear a collar and tag, and a chip is a backstop that only works once the dog reaches somebody with a scanner. The tag is what works in the hands of the person who actually has your dog. The full position is in our UK dog collar and tag law guide.

• For an engraved tag, choose a hard metal like stainless steel, with deep-cut lettering, over brass or bare aluminium.
• Use a proper split ring, or a small screw-gate or locking link, not a thin jump ring. Here's how to fit a split ring without breaking a nail.
• Put the tag on its own ring on the collar rather than on the D-ring you clip the lead to.
• A slide-on tag that sits flat against the collar cannot swing, so it doesn't rub or jingle and there is no ring to open.
• Keep two forms of ID rather than one, so a failure isn't total.

That last point is the one that matters most. Our QR code dog tags have the code printed into the tag as a flush black inlay rather than cut into soft metal, so there is no lettering to polish away, and the details behind the code are changed from your phone rather than by buying a new tag. You can run one of those alongside an engraved tag with your name and address, which is the arrangement we set out in QR tag or engraved tag.