Dog lovers might take issue with this fact, but dogs can actually damage your lawn a lot without wanting to. If you let them loose on the lawn, that can lead to types of damage you might not even think of right away, and it can also cause problems that are difficult to fix.
First there is the obvious: dogs love to play around in the dirt. If you set them loose on your beautiful, green lawn, they may love it and play around a lot, but the result will be that a large part of the turf could be damaged. Grass blades and their roots are pretty sensitive, and you need to take that fact into account before allowing your dogs to run loose on the lawn.
Another issue, and a potentially more problematic one, is that dogs tend to urinate on the lawn to mark their territory. This is a very natural tendency for the dog, but it can wreak havoc leaving you to ask how to bring back dead grass from dog urine on your lawn. The added nitrogen from the urine will go into the soil and cause a burning effect that parts of the lawn may never recover from. This leads to unsightly brown spots which have to be treated right away, as otherwise they could lead to areas of the grass dying or becoming very weak.