Sashiko is often used for visible mending of clothing, especially jeans. The technique is well suited because the dense stitches can reinforce worn areas while making the repair decorative.
If a piece of fabric has a hole, you can first place a piece of fabric behind the torn area. Then sew sashiko stitches through both the fabric and the patch behind.
The stitches hold the repair together and at the same time make the area stronger. Many people choose to have the stitches form a pattern over the repair, making the repair part of the garment's design.
This way, a pair of worn jeans can get a new life instead of being discarded.