I finally called a lawn service two weeks ago. My lawn full of dandelions
was completely devoid of the yellow flowers and seed heads two days after
they sprayed it, and a week later there was no sign of the weed at all.

The lawn service aerated my lawn three days ago and after a good watering,
the grass is greener and fuller than I have ever seen it.

They will return in another two weeks to treat for crabgrass.

Unless ALL your near-by neighbors con troll the dandelions and crabgrass in
their yards, your chances of controlling them in your lawn by just pulling
them, especially in a larger yard, are next to nil.