Inspect the roof for damage after heavy winter storms.
Inspect gutters or downspouts for leaks.
Keep gutters clean of ice and debris.
Check for draft around windows and doors. Caulk and repair weather stripping as necessary.
Check to make sure all outsides vents are not blocked by snow or debris.
Plumbing
Pour hot soapy water down seldom used drains to prevent sewer gas backup.
Inspect sink drains and plumbing shut off valves for signs of corrosion or leaks.
Check that toilets are secure and the water fill valve is shutting off after the toilet tank fills up.
Clean out faucet aerators and shower heads.
Inspect caulking around sinks, showers & bathtubs. Re-caulk as necessary.
Interior
Change or clean the furnace filter.
Test smoke and carbon monoxide detectors.
Clean bathroom exhaust vents and grills.
Clean ceiling fan blades.
Vacuum out the supply and return heating registers.
Check fire escape routes, door and window lock as well as outdoor lights.
Electrical
Test all GFI outlets by pressing the Test button. The button should pop out and the power to the outlet should go off. Press in the Rest button and the power to the outlet should go back on.
Check for frayed appliance cords.
Exercise the operating mechanism of the circuit breakers.
Appliances
Disposal-grind ice cubes and lemons to clean and deodorize, flush with hot water.
Clean strainer and spray arm, and run a wash cycle with vinegar to clean.
Clean out kitchen exhaust fan/filters with hot soapy water or detergent.