I have found that just killing the damned weeds has turned my lawn around. I used to have a ton of them then I just got a few of the spray bottles of Spectracide weed killer, and sprayed each weed individually. They shriveled up, turned black, then disappeared. Lawn finally looks very presentable. If I missed any I just did a round 2.
I care, but not that much since I am renting, but then again I am pretty much a Godsend to landlords lol. Also my yard is small.
I'd PM BrianZO6 as stated above... he could at least answer your questions professionally!