Geckos like warmth, water, and places to hide. You can do several things to make sure your home doesn’t offer these amenities.  Maintain the general cleanliness of your home by keeping the floor swept and not leaving piles of stuff lying around, such as laundry, newspapers, boxes, etc.  Keep your furniture six inches from the walls and don’t hang up many pictures: geckos are nocturnal and like warm, dark places to hide out during the day.  Keep your thermostat turned down as low as you can handle: geckos like the warmth and humidity of your home when it gets cool at night.  If you have any leaky faucets or pipes or any area that generally offers stagnant water in a humid environment – fix them and remove the water because geckos are drawn to those environments. Your backyard can be a welcome mat to your home if geckos are drawn there by their creature comforts: water, insects, and cover. Here are some guidelines to follow in order to make your yard less welcoming:  Remove any places where water can stagnate, such as birdbaths, as these are the breeding grounds for insects geckos prey upon and sources of hydration to geckos.  Water your yard sparingly, as lizards enjoy the moist environment and will drink the water for hydration.  Do not plant succulents: if a gecko cannot find any water for hydration, it will nibble on succulents to survive.  Trim back your bushes, especially those close to your house, because geckos love places to hide.  Placing some netting over your shrubs will keep geckos from using them as hideouts.  Use outdoor lighting sparingly, as it draws insects that geckos prey upon. If you must use outdoor lighting, consider sodium vapor or yellow lights. Geckos can squeeze their little scaly bodies into small crevices and holes, so make sure your home is well sealed. Walk around the inside and outside of your home and fill any cracks with caulk and make sure your windows and venting are screened properly.
Render your home inhospitable to geckos. Render your backyard inhospitable to geckos. Ensure your home is sealed.