Carbon monoxide detectors are essential this time of year in case your furnace malfunctions.
Carbon monoxide is a colorless and odorless gas that usually goes unnoticed without a detector.
Every house should have at least one fire extinguisher, ideally two. The size of your fire extinguisher is dictated by need. GFI boxes should be in every bathroom and kitchen. Electrical appliances and water don't mix and this device will cut off current when properly installed. Household chemicals are the most overlooked safety hazard.