Match the height to your grass type
Different grasses tolerate very different heights. Some fine-textured warm-season grasses handle close mowing well; most cool-season lawns do better on the taller side, especially through summer. Identifying your grass is the first step to choosing a height.
Follow the one-third rule
Try not to remove more than about a third of the blade in a single cut. Taking more at once stresses the plant and can leave it slower to recover. If the lawn got away from you, cut it in stages a few days apart rather than all at once.
Keep the blade sharp
A sharp blade slices cleanly; a dull one tears. Torn tips lose moisture faster and discolor. Sharpening a few times per season is a small effort with a visible result.
Taller grass competes better with weeds
Higher turf shades the soil surface, and less light at the surface generally means fewer weed seeds germinating. Raising the mower is often a more sustainable weed strategy than repeated spraying.