When we bought our house we replaced all the knobs with latches. A few years later, when the grandkids began showing up, we found out just how much easier we made it for them to open doors.
+1@ Kids defeat latches easily. They watch you do it a couple of times and that's all it takes. Best advice is to move dangerous kitchen and bathroom things out of reach. Plug all the outlets. Keep them out of laundry area with pet gates. Attach door locks or latches 5 ft high for doors going outside and into the garage.