One important factor in maintaining a quality lawn is the sharp blade of the mower.
When we cut a lawn each blade of grass sustains a wound. A sharp blade on a recently serviced mower will leave a clean, straight edge. The slice in the leaf will heal quickly. A fast recovery gives less opportunity for disease to stress the plant. A healthy plant looks good so overall the lawn appears well.
If the cutting blade is blunt it will bash and tear individual blades of grass. A substantial area at the end of each leaf will be grazed. The tissue will not be able to heal quickly and the plants will be stressed. The most expensive cutting machines produce a poor quality lawn if they go too long without being sharpened or if blades sustain damage on an uneven surface.
To keep blades sharp the lawn needs to be level and clear of stones or other debris. A sharpened blade will soon go blunt if it hits stones. Also uneven ground will cause the mower to scalp. If one side of a cutting machine dips into a rut the blades may touch the ground. This causes patches of grass to be cut at ground level (scalping). Apart from small areas of damage to the lawn an issue with scalping is the damage it causes to the cutting blades. Once they touch the ground cutting blades can become blunt instantly.
A quality lawn relies upon sowing cultivated species of grass that establish into healthy plants. The weeds need control and edgings have to be maintained. The selection of species to suit the aspect and use of the lawn are important.
Then a sharp cutting blade on the mower is paramount to presenting a lawn in its best condition.