Lawn sprinkler heads are designed to remain just above the ground, so they can evenly water your lawn. However, this also means that they're vulnerable to being hit by a lawn mower. A single strike can damage or break the head, leading to an uneven or patchy lawn. The best way to protect your sprinkler heads is to mark them with tall stakes or flags. This will make them visible and avoid accidental mowing. You should also be careful when mowing around the heads, using a slow and steady motion. If you do accidentally hit a head, shut off the water immediately and check for damage. In most cases, the head can be easily replaced. Also, there is an option to place a layer of metal wire mesh or chicken wire around the top of the sprinkler head so that the blade of the mower won't be able to cut it. Another option is to install plastic covers over your sprinkler heads so that they're shielded from the blades of the mower. Whichever option you choose, make sure that you check regularly to make sure that the mesh or cover hasn't been tampered with or moved out of place.