Fall is the last comfortable window for exterior work. Here is what is actually worth your time.
1. Wash the concrete before the leaves sit on it
Wet leaves left on a driveway or patio leach tannin into the surface, and that brown shadow is considerably more stubborn than the dirt it lands on. Washing before leaf drop rather than after is the difference between one job and one job plus a stain.
2. Clear the gutters after the leaves finish
Not during. Clearing gutters halfway through leaf drop means doing it twice. Wait until the trees are mostly bare.
3. Check where water lands
Walk the property during the next real rain. Look for where runoff pools against the foundation or splashes mud onto siding. Those spots become the stains you call someone about in spring.
4. Get the green off the north side
Anything shaded stays damp, and anything that stays damp grows algae. The north and east faces of a house are where it starts. It comes off easily now and gets stubborn if it overwinters.
5. Decide about Christmas lights
Not book them necessarily — just decide. Knowing whether you want lights this year, and roughly where, is the thing that determines whether the install is relaxed or rushed.
None of this is urgent. All of it is easier now than it will be in six weeks.