An add on here. We have a heavily forested backyard with a lot of oaks. We do not mulch in place otherwise the leaf litter would not decompose in time for spring. And instead of grown ground cover, we would have rotting layer of leaves. We do two passes with the rake to clean off leaves (compost some, bag some), and then we do the last pass in November with the mower to mulch the remaining leaves.

So depending on your yard, you may not be able to do a pure mulch-in-place method.