Inspect exterior walls, doors and windows. Check walls and window sills for damage such as cracks, gaps, loose or crumbling mortar, along with splitting and decaying wood. Caulk exterior joints around windows and doors, which helps keep the home weather tight and lower heating bills. Check windows and doors to make sure locks work properly and that they are in good condition. Clean tracks and lubricate hinges. Repair or replace any cracked windows.