Pre-emergent for winter weeds should go down in the early fall. Pre-emergent for summer weeds should be going down now. If you already have a winter weed problem, pre-emergents won't help. You'll need a post emergent for that.
Unfortunately, we'll probably have a big problem with brown patch this spring with the wet winter. The fungus is no longer active after temps get to the 70's so by the time you see it the damage is done. Hope this helps!
If there is anything we can do to help, feel free to give us a call and we can tell you more about our lawn care services. 979-705-9545 or
https://greenerlawnscapes.com/contact/-Daniel Sherrod