The once-a-year list for a house

These are the jobs a house needs once a year, by season.

Fall, before the heat comes on

Have the furnace serviced. The Consumer Product Safety Commission urges a yearly professional inspection of every fuel-burning appliance to prevent carbon monoxide poisoning.
Change the furnace filter and write down the size. Then change it on the schedule the manual gives.
Clean the gutters once the leaves are down, and check that the downspouts carry water away from the foundation.
Shut off and drain outside faucets and the irrigation system before the first hard freeze. The Insurance Information Institute covers this in its cold-weather guidance.
Test the smoke and carbon monoxide alarms. The U.S. Fire Administration says to test alarms monthly, change batteries at least once a year, and replace the alarms every ten years.

Winter

Watch the roof edge for ice dams after heavy snow. They mean heat is escaping into the attic. The University of Minnesota Extension explains why, and says sealing and insulating the attic is the long-term fix.
Check the filter again.
Find the main water shutoff and make sure it turns. The III says to learn where it is before you need it.

Spring

Flush the water heater and check its temperature and pressure relief valve. The EPA's WaterSense checklist lists both and says a professional can do it.
Look over the roof from the ground with binoculars for lifted or missing shingles.
Have the air conditioner serviced before the first hot week.
Check that the soil around the house slopes away from the foundation.

Summer

Clean the dryer vent all the way to the outside. The U.S. Fire Administration says to clean the vent and exhaust duct, and to check that air is coming out of the outside vent while the dryer runs.
Check the caulk around windows and doors and the seal around the tub and shower.
Check the deck for soft boards and loose rails.

Any time

Keep a list of the ages of the big systems. By InterNACHI's chart, a water heater is near the end of its life past 10 years and a furnace past 15.

Where Lyle comes in

Tell Lyle the filter size once and it reminds you when it's due, with the part number. Tell it when the furnace was last serviced and it reminds you about the next one. Everything done on the house goes into its history.