How often to replace your dog's harness and leash

Key points

• There's no expiration date: replace them as soon as you see split seams, cracked buckles, a clip that doesn't close properly or frayed webbing.
• Glance at the clip and buckles before every walk and give everything a thorough check once a month.
• The two-finger rule: you should be able to fit two fingers between the strap and your dog's body, no more, no less.
• Puppies grow very fast: check the fit every week and go up a size when the harness reaches the end of its adjustment.
• Chafing in the armpits, on the chest or neck means the harness doesn't fit well or has gone stiff.

How often should you replace your dog's harness and leash? There's no fixed date: it depends on how much they're used, the material, how hard your dog pulls and whether they get wet, chewed or spend the summer at the beach. What there is, though, are clear signs that it's time for new ones, and they're worth knowing, because a worn-out clip or a split seam gives no warning: it fails all at once, often at the worst moment, next to a road or when a cat runs past.

In this guide you'll find what to check and how often, how to make sure the harness or collar fits with the two-finger rule, what to do with puppies that grow every week, when a harness is better and when a collar is, how to wash them without ruining them and how to measure your dog to get the size right.

How often to replace them

A harness or leash doesn't expire, it wears out. A nylon one used for a short while each day with a calm dog can last for years; the same one, on a big dog who pulls, swims in the river and chews it in the car, can be useless within a few months. So rather than a date, what helps is a checking routine:

When	What to check
Before every walk (10 seconds)	That the clip snaps shut on its own and all the way, and that the buckles click and don't open when you pull.
Once a month	A thorough check: seams, webbing, rings, buckles, reflective strips and the fit on your dog.
Every week, for puppies	The fit: at that age they can change size within a month.
After washing	That nothing has warped or shrunk and that everything is completely dry before use.
After a scare	After a very hard yank, a snag or a bite, check everything even if it looks intact.

If you have doubts about a piece, replace it. A new harness or leash costs far less than a dog running loose in the middle of the street.

Signs of wear

Check it in good light, bending the webbing with your hands and pulling on every point where pieces join.

• Seams: loose threads, open stitches or seams pulling apart, especially where straps attach to the rings and at the leash handle. That's usually the first place it breaks.
• Plastic buckles that are cracked, whitish, don't click or open if you pull hard on both sides.
• Clip (snap hook): a weak spring, a gate that doesn't spring back on its own, rust, play, or one that opens when twisted. If you have to help it close, replace it.
• Rings that are bent, open or rusty.
• Webbing that is frayed, thinner in some areas, cut or covered in tooth marks.
• Stiff or crusty webbing: salt water, sweat, mud and sun harden nylon and make it rough. A stiff harness rubs more and is weaker.
• Badly faded color: sunlight degrades synthetic fibers; if it has lost a lot of color, it has lost strength too.
• Velcro that no longer grips, reflective strips peeling off and, on leather, cracks or dried-out patches.
• Retractable leashes: a frayed cord or tape, a brake that doesn't lock instantly, or a broken casing. If the cord is damaged, the whole leash is done.

Signs on your dog

Look at your dog as well, especially after the first few walks with new gear and in summer:

• Chafing or redness in the armpits, behind the front legs, on the chest or the neck.
• Broken or shorter fur, or bald patches where the straps sit.
• Scratching or chewing right there, or walking oddly, with short steps or elbows sticking out.

If the skin is irritated, stop using that harness until it heals and check the size and fit. If the sore doesn't improve within a few days or it oozes, have your vet look at it.

How to check the fit: the two-finger rule

A well-fitted harness or collar neither squeezes nor slides around. The simplest way to check:

1. With your dog standing calmly, slide two flat fingers, one on top of the other, between the strap and their body.
2. Do it on every strap: neck, chest and the one that goes behind the front legs.
3. If they don't fit, it's too tight. If your whole hand fits, it's loose and your dog could slip out.

Also:

• The belly strap should sit about four finger-widths behind the armpits so it doesn't rub them.
• Escape test: with the harness on, gently pull the ring backward and upward, the way a dog backing up would. If it slides over their head or a leg comes out, tighten it.
• Free shoulders: with a Y-shaped harness, the chest strap runs down the breastbone and leaves the shoulders free. Harnesses with a horizontal strap across the front of the chest can restrict movement when walking.
• Collar: two fingers of room, and your dog shouldn't be able to pull it over their head when backing up. Dogs with narrow heads, like greyhounds and other sighthounds, slip out of a regular collar easily.
• Check again if your dog gains or loses weight, after a short haircut or, the other way round, when the winter coat comes in.

Puppies: they outgrow their harness fast

A puppy can change size in a few weeks, and large breeds keep growing past their first birthday. A few tips:

• Check the fit every week with the two-finger rule.
• Don't buy a bigger size “to grow into”: a harness that slides around can come off, rubs and teaches your puppy that escaping is possible.
• Choose a very adjustable one and, when you buy it, make sure your puppy's measurements fall at the low end of its adjustment range: that leaves room to grow.
• Go up a size when it's adjusted to the maximum and two fingers no longer fit.
• Get them used to it gradually: let them wear it for a few minutes at home, with treats, before heading out with it.
• Puppies chew everything: don't leave them with the harness or leash on unsupervised, or to sleep in.

Harness or collar

Both are fine; what matters is that whichever you choose is in good condition and fits well.

	Harness	Collar
Where the pressure goes	On the chest and torso	On the neck, where the trachea and cervical spine are
Best for	Dogs that pull, puppies, small breeds prone to tracheal problems, flat-faced dogs (bulldogs, pugs) and dogs with neck or back problems	Dogs that walk without pulling, and for carrying the ID tag
Watch for	Chafing in the armpits, and that it leaves the shoulders free	That it isn't too tight and can't slip over the head

Many dogs wear both: a collar with the ID tag and a harness to clip the leash to. And even if your dog is microchipped, a tag with your phone number means whoever finds them can reach you within minutes.

We don't recommend choke, prong or shock collars: they hurt and don't teach a dog to walk any better.

And the leash

For everyday walks in town, a fixed leash of 4 to 6 feet (1.2 to 2 m) is the safest choice. Retractable leashes give little control near traffic, their cord can cause burns or cuts if it wraps around a leg, and they're a poor idea for dogs that pull. Check the whole leash, not just the clip: the handle and its seam take every tug.

How to wash a harness and leash

A clean harness lasts longer and rubs less: dried sand, salt and mud act like sandpaper on the webbing and on your dog's skin.

• Nylon, polyester and neoprene: by hand, in lukewarm water with a mild soap or a dog shampoo, scrubbing dirty areas with a soft brush. Rinse very well so no soap residue is left to irritate the skin.
• In the washing machine, only if the manufacturer allows it: inside a mesh laundry bag or a closed pillowcase, on a delicate cycle at 30 °C / 86 °F at most. Fasten the buckles and Velcro first.
• Leather: never soak it or machine-wash it. Wipe it with a damp cloth and a little leather soap, let it dry away from heat and condition it now and then with a leather conditioner.
• Retractable leashes: don't submerge them. Pull the cord or tape all the way out, wipe it with a damp cloth and let it dry fully extended before retracting it.
• After the beach or the pool, rinse with fresh water even if you don't wash with soap: salt and chlorine stiffen the webbing and rust the metal.
• Drying: air-dry in the shade, completely, before using it again. No dryer or radiator, which warp buckles and stiffen the webbing. A damp harness chafes and ends up smelling bad.
• Avoid bleach, fabric softener and strong fragrances: they weaken the fibers and can irritate your dog's skin.

If you feel like giving your dog a bath too, we explain how in our homemade dog shampoo.

What you need

• Flexible tape measure, the sewing kind (or a piece of string and a ruler)
• Small treats
• Pen and paper, or your phone, to note down the measurements
• A scale, to know your dog's weight
• The size chart for the harness or collar you want to buy

Step by step

1. Pick a calm moment

   After a walk is best, with your dog relaxed and standing square on all four legs, head in a natural position. If your dog gets restless, stop and reward: you can measure in two sessions.

2. Measure the chest girth

   Wrap the tape around the widest part of the chest, just behind the front legs. Snug but not tight: it should sit against the body, not sink into the fur. This is the most important measurement for a harness.

3. Measure the neck

   Go around the base of the neck, where a collar would sit, a few finger-widths above the shoulders. On dogs with a lot of fur, press a little so the tape reaches the skin.

4. Weigh your dog and note it all down

   Write down chest, neck and weight. Some size charts also use back length, from the base of the neck to the base of the tail: if the chart asks for it, measure it with the tape lying along the back.

5. Compare with the size chart

   Each brand has its own chart. Choose the size where your measurements fall within the adjustment range; for puppies, the one where their measurements sit at the low end of the range so there's room to grow.

6. Adjust and check

   Put it on, adjust the straps and apply the two-finger rule to each one. Do the escape test by gently pulling the ring backward and, after the first few walks, check the armpits and chest for chafing.

Frequently asked questions

How often should you replace a dog harness?

There's no fixed date: replace it when it shows wear, such as split seams, cracked buckles, a clip that doesn't close on its own, or frayed or stiff webbing, or when it no longer fits your dog well. Check the clip before every walk and do a thorough check once a month. For puppies, check the size every week.

How do I know if my dog's harness fits properly?

Use the two-finger rule: you should be able to slide two flat fingers between each strap and your dog's body, no more, no less. The belly strap should sit about four finger-widths behind the armpits, and the shoulders should move freely. Gently pull the ring backward: if a leg or the head slips out, it's too loose.

Is a harness or a collar better for a dog?

For leash walking, a harness is usually better because it spreads the pressure across the chest instead of the neck. It's especially recommended for dogs that pull, puppies, small breeds with delicate tracheas and flat-faced dogs. A collar works for dogs that walk without pulling and for carrying the ID tag. What matters is that it's in good condition and fits well.

Can you wash a dog harness in the washing machine?

Nylon or polyester ones usually can, if the manufacturer allows it: inside a mesh laundry bag, on a delicate cycle at 30 °C / 86 °F at most, with the buckles fastened. Air-dry it in the shade, never in the dryer or on a radiator. Leather harnesses don't go in the washing machine: clean them with a damp cloth.

How do I know what size harness my dog needs?

With a flexible tape measure, measure around the widest part of the chest, just behind the front legs, and around the neck where a collar would sit. Weigh your dog too. Compare those numbers with the manufacturer's size chart, since sizes vary from brand to brand, and for a puppy choose the size that leaves room to grow.