One of the reasons we encourage ongoing lawn mowing through the fall is your leaves. Leave actually offer your grass some nutrition in the form of nitrogen when they decay. But, they left out in the lawn as they are will create a mat over your grass and can actually choke it out, especially when the leaves are wet. So it is important to mulch them. Mulching shreds the leaves into small particles that decay more quickly, offering up that nitrogen. It’s also important not to wait until all of your leaves fall to mulch them. Leaf litter is one of the many things that contribute to the thatch layer. Too thick of a thatch layer can suffocate your lawn as well. Hope this helps and if you have any questions, let us know!