A waistband elastic that survives many washes

Short answer: A wide elastic with a woven pattern lasts longer than a thin, smooth one. Look for a band three to four centimetres wide.

What wears elastic out

Heat and chlorine. Tumble dryers, radiators and water that is too hot make the rubber core brittle. That is why waistbands give after a year rather than after five.

What a good one looks like

Wide, evenly woven and firm to pull. Stretch it to double width and let go. If it springs all the way back, it is sound. See bamboo boxer briefs for men.

Sewn in or laid on top

An elastic sewn into the fabric feels softer but can roll. An external elastic with a logo holds its shape better. Both work. See bamboo briefs for women and bamboo underwear for men.

Frequently asked questions

Can an elastic be replaced

Yes, but it means sewing. Often it is not worth the trouble.

Why does the waistband roll down

Because the elastic is narrower than it should be for that amount of fabric.

Does washing at 40 degrees help

Yes, compared with 60. Elastic lasts markedly longer at a low temperature.