No matter how carefully you've childproofed the house, great-aunt Jane has probably not applied your standards to her purse. Aspirin and other items that people typically carry with them are dangerous to small children. Children start pulling up on things shortly after they start crawling. And when they learn how to climb, watch out. Some kids will scale counters, bookcases, and anything else they can get a grip on.
Most parents consider safety gates essential safety items.
Unfortunately, some safety gates can themselves pose a hazard to children. In general, look for gates that your child cannot dislodge but that you can easily open and close. Choose one with a straight top edge and a rigid mesh screen to keep your child out of rooms that are off-limits. Place another one three steps from the bottom. If you plan to use an older gate with V-shaped openings, make sure the openings are too small for a child's head and neck to fit into.