Key is to create an environment for grass to thrive. Suggest getting your soil tested to learn PH levels, etc. In my state (MA) our state school (UMass) offers soil tests for $15. With a large yard, I'd probably test 2-4 areas, focusing on trouble areas.
UMass will test the soil and recommend how to amend the soil to create optimal environment for grass - typically an 18-24 month plan.
Once your soil is favorable for grass to grow, and assuming you have top soil, grass will outpace most all weeds.
I have an acre of grass in MA (near Foxboro) and have not used any weed products in the 8 years I have lived in the home - lawn is virtually free of weeds except for clover mixed in and the rogue dandelion.
Also, set mower high (I cut 3 1/2") to promote healthy grass and shade out weeds.
A year ago, I a small area was having issues with crab grass - had the soil tested, learn my PH was way low. A year later, PH is back up and grass has outpaced the crabgrass.
Cheers,
Brendan