I think you missed the point. A healthy lawn won't allow dandelions and other weeds (not clover) to grow. The chemical fertilizers you're putting on the grass are doing the same thing as mulching your clippings (adding nitrogen to the soil). If you mulch your clippings (go over them twice if they're thick) you can't see them, so you won't have "clippings and leaves scattered all over it ". As for the leaves, this is done in the last part of the year after all the leaves have fallen so it's not like you're out enjoying your lawn anymore. He's not saying don't do anything to your yard, he clearly told you what to do, and that is not spreading chemical fertilizers that find their way into salmon streams and dangerous herbicides. I've been following this advice on my lawn which was neglected by previous owners and it's looking great so far.