Julian, I use a spring pre-emergent with low nitrogen, say @ 18. I try to minimize how much nitrogen I add in the spring since it just makes me have to cut the grass more. Hit the grubs in June or so to keep the moles down. I spot treat with a fungicide where necessary. I aerate and fertilize in the fall. I have done this for many years. I have over seeded in the fall a couple times over the years. We did add a sprinkler system 3-4 year ago and water 1"/week. Adding the sprinkler system did help immensely with thinning over the season due to heat/water etc...
I've gotten it to the point I keep hand spray bottles of lawn weed killer I can use to walk around the yard and spray weeds with. Don't want to carry a 2 gal tank sprayer around anymore. I use a variety of chemicals in small spray bottles, this way I use less. I use an extended kill weed/grass inside the beds on stuff when it comes up. I had some aggressive viburnum that was sending up shoots off the roots into the yard and other beds. Had my landscape guy remove this and grind the bed for the roots and planted better choices. I've been using brush kill full strength where the roots are still sending up shoots in the beds it was growing in. Landscaping is a very much learn by doing experience. Thanks. Brian
Brian