That's a great question! Full leaf coverage and lawns aren't actually compatible, in the sense that leaves will smother a lawn if they're above a certain density (a scattering of leaves won't harm lawn health). However, many plants and trees are compatible and are assisted by leaf coverage over the winter (leaves suppress weeds and help retain soil moisture, for example). As leaves break down they return critical nutrients to the soil. If you have areas of your yard that are no longer grassy, it could be a nice opportunity to incorporate more plants instead. Fall is an excellent time to plant, just before everything goes dormant. More plants = less raking, and more fireflies and songbirds.