Headphones have a weak point at the plug which can cause audio dropouts when flexed. Here's how to stop that happening.

Take a regular clicky retractable ballpoint pen.

Open the end and remove the spring.

Wrap the spring around the headphone cable - start in the middle of the spring and wrap one way first.

Keep rotating the cable when you get to the end of the spring, so the cable now runs inside half of the spring.

Complete the same process on the other half of the spring.

The cable should now be completely inside the spring.

Slide the spring towards the plug as far as it will go - it will now protect the cable against damage when flexing.

Select a piece of heat-shrink tubing large enough to fit over the headphone plug.

Measure the distance from the end of the spring to edge of the plug, leaving the connector free.

Cut the heat-shrink tubing to length.

Double check the heat-shrink tubing covers just the spring to edge of the plug.

Slide the tubing over the plug and line it up with the edge, ensuring the connector isn't covered.

Cut two small pieces of foil, approximately 4cm square.

Wrap one piece of foil around the cable to protect it, and slide it up to the spring.

Wrap the other piece of foil around the connector.

Use a heat gun on high setting, with as small a nozzle as possible.

Wear protective gloves for the next stage to shield your hands from the heat.

Keeping the cable rotating at all times, heat the tubing for around 30 seconds until it won't shrink any further.

IMPORTANT - let everything cool for a few minutes as it will be hot, then remove the protective foil from both sides.

The tubing will keep the spring in place and stop if catching on clothing and prevent damage from flexing.