Hardware fails before cloth does and it is the cheapest thing to fix

The moving parts of a garment

Almost everything in a garment is passive. The cloth sits there, the seams hold it together, and neither has to do anything but stay put. The fastenings are the exception: they are operated, often twice a day, and they take concentrated force in small places.

That is why they fail first. A zip on a jacket worn daily is opened and closed a couple of thousand times a year, and each cycle drags a slider along a set of teeth. A button on a waistband takes the entire tension of the garment at a single point.

The reason this matters is economic rather than technical. A failed fastening ends the useful life of a garment whose fabric has years left, and replacing it usually costs a small fraction of replacing the garment.

How a zip actually works, and how it stops

A zip does not simply pull two rows of teeth together. The slider is a wedge with channels cut through it that forces each tooth to rotate and interlock with the one opposite, and it holds them at exactly the angle where they cannot come apart under sideways load.

Almost every zip failure is a slider failure. The slider is usually softer metal or moulded plastic, and its channels wear open with use. Once it no longer squeezes the teeth to the right angle, the zip closes and then springs open behind the slider, which is the classic symptom.

The teeth themselves are frequently fine. This is why a good repair often means replacing only the slider — a job a shoe repairer or alteration shop does quickly — rather than replacing the whole zip, which means unpicking and restitching a seam.

Coil, tooth and the difference in behaviour

The two common constructions behave differently. A coil zip is a continuous monofilament spiral stitched to the tape; it is flexible, light, and it can often be persuaded back into engagement after a jam because the coil deforms and recovers. A moulded-tooth or metal zip has separate teeth, is stronger under load, and breaks properly when it breaks.

Metal zips wear differently again. The teeth are crimped onto the tape and can loosen, and a single missing or bent tooth ends the zip because the slider cannot pass the gap. They also benefit from lubrication, which sounds fussy and takes seconds — a graphite pencil rubbed along the teeth is the traditional method.

Most jams are not mechanical failures at all. They are fabric or lining caught in the slider, and forcing it is what turns a jam into a break. Ease the caught material back out along the direction it went in, then work the slider gently.

Buttons come off because of the shank, not the thread

A button needs a gap between itself and the cloth so the buttonhole layer has somewhere to sit. On a sew-through button that gap is created by wrapping the thread beneath the button to form a shank; on a shank button it is moulded in.

Buttons sewn flat against the fabric have no shank, so every time the garment is buttoned the threads are strained sideways against the edge of the holes and abraded. That is why the same button keeps coming off, and it is why a machine-sewn button on a heavy coat rarely lasts.

The other common failure is that the buttonhole stretches or frays before the button goes anywhere, which is a fabric problem and needs the hole reinforced or restitched. On tailored garments the front buttons should be sewn with a generous shank, and a small reinforcing button on the inside spreads the load through the cloth.

The parts nobody thinks about until they go

Waistband hooks bend and stop catching. Press studs lose their spring, usually because the socket half has been forced open by repeated pulling apart rather than unsnapping. Drawcord ends fray back through their channel and disappear, which is easily prevented by knotting them and easily fixed with a safety pin and patience.

Elastic in waistbands dies chemically as well as mechanically, since the same degradation that affects elastane in fabric affects it in a band. Most elasticated waistbands are made with a casing so the elastic can be pulled out and replaced.

Belt loops tear at the top because they take the whole load of a belt being tugged. They are two lines of stitching and take a couple of minutes to reattach, but if a loop has torn the cloth rather than the thread, a patch behind it is needed or it will simply tear again.

Keeping the spares and doing the repair early

Most decent garments come with a spare button, usually attached inside a seam or in a small bag. Cut it off and keep it somewhere central, because attached spares get lost with the garment they came with, and matching a button afterwards is far harder than it sounds.

The general rule is that hardware repairs get more expensive the longer they are left. A loose button is thirty seconds of sewing; a lost button is a hunt. A worn slider is a cheap swap; a zip forced until a tooth is gone is a full replacement with seam work.

It is worth being frank that not every repair is worth doing. Replacing a zip in a cheap garment can cost more than the garment did, and nobody should feel obliged. But on anything decent, hardware is the highest-return repair there is, because it restores full function to something otherwise intact.