As nighttime temperatures gradually fall below 65F, consider possibly over-seeding your lawn with annual ryegrass or winter clover.
Over-seeding our warm season lawns in Central Texas is not wide spread, but can be extremely beneficial, especially if you want year-around green lawn, have patchy lawn, or are planning to sell your property during colder months of the year.
Pros:
Your lawn should remain green during winter even as your Bermuda/Zoysia goes dormant (from first hard freeze until usually April, depending on strength of your lawn).
If you have patchy lawn, growing grass with roots in the ground will keep your soil alive, reduce compaction and erosion, and make it easier to repair your lawn next Spring.
Both annual ryegrass and winter clover will die next April as your warm season lawn starts waking up, which reduces competition (they are also both trivial to kill with herbicides if needed).
Cons:
If your warm season lawn is already in good shape, it can be somewhat relaxing to let it go dormant and take a few months off from mowing.
While cool-season lawn will reduce rate of winter weed germination, it will also make it harder to use herbicides to kill weeds (especially Poa Annua, as it is a cold season grass, same as rye grass).
You will not be able to apply winter pre-emergent herbicides as they will prevent rye grass or clover seeds from growing.