I have some compaction near the street curb which is a few hundred feet long. I am going to dig a bit of the dirt out and put some better black top soil in there, plus some KBG see. My lawn was originally seeded from scratch by a builder with who knows what grass seed. I over-seeded with straight Midnight KGB two years in a row (Late August core aeration/seed/starter fert.) and it really improved the lawn. I am very happy with that procedure which seems to have made my lawn into a much higher density KGB lawn than it was before. I am also hoping that the lawn is more resistant to rust than it has been in past years. This Fall I plan to just aerate and put down starter fertilizer without seed because (other than teh curb area) it looks like the Midnight took over very nicely.

You are not supposed to seed after applying weed control. Wintergaurd (based on what I read) is mostly fertilizer. So I think it's ok to seed now (if the temp where you are does not dip below 50 degress F). Here is what Scotts recommends: http://www.scotts.com/smg/learn/infoHowToArticle.jsp?detailId=14900060 Here is a snippet from that page: Feeding in the Fall Wait a minute. Isn't fall when lawns start to shut down? Why fertilize then? Fall conditions are great for lawns. Grass roots start to store nutrients the grass will need when it wakes up again in the spring. So you want to help those roots grow by fertilizing. Your best bet is to feed once in early fall (if you are overseeding, your starter fertilizer counts) and once more about 6 to 8 weeks later, around Thanksgiving. Scotts® WinterGuard® Lawn Fertilizer is formulated to deliver the nutrients grass needs to get through the winter and come up strong the following year.

Unless you are seeding zoysia or bermuda grass, then EARLY FALL IS ALWAYS THE BEST TIME TO SEED. The next best time is mid fall. If you wait until late fall then you don't have a chance to fill in any thin spots where you didn't get enough grass seed the first time. Spring is the second worst time of year to seed with summer being the worst. Even winter can be an better than spring or summer under certain circumstances.

Yup, too late to seed now in CT. For CT, Sept. 1 is a good time, give or take a week. Next year you can do this yourself if you want to, Home Depot or other rental places carry the equipment, as long as you don't have too much area. Core aeration might not be necessary if your soil is good, but if you do core aerate I recommend following it up with a power rake.