Milky spores work from Long Island south - said the late Ralph Snodsmith. Most of New England and all of Maine is too far north.
My lawn in Bangor looks absolutely the best it's ever been. Very few weeds, thick, luxuriant turf. Sure, it needs mowing twice a week with all the rain we have received ( 8.28" rain in September ). It took 13 years for the lawn to recover from grubs to get to the point where it is right now. I had a long siege of sod webworms this summer but otherwise the lawn is in good shape. Purdue recommends a late fall (November) application of urea - which I have done for 15 plus years with good results for an earlier green up in the spring.
If a pre-emergent weed killer is used in the spring any de-thatching or aeration done after that application will render the pre-emergent ineffective. Pre-emergents will allow turf to fill in via rhizomes but will not allow reseeding much success.