When I had my first child, I made a child-proofing to-do list. One of the things on that list was putting child-proof locks on all the lower cabinet doors in the kitchen. I ended up only doing one—locking the cabinet under the sink where we store household chemicals—because buying the locks and installing them was such a pain.
Later on, I discovered that sometimes the best solution is the cheapest and easiest solution. All I had to do was put a rubber band on the cabinet door knobs. It made the cabinet doors frustrating for my small kids to play with.
Of course, the other part of it is to teach your children what they are allowed to play with and what they aren’t allowed to play with. Young kids are impressionable, and if you consistently stop them from playing with certain things like electrical outlets, doors, or knives, they will eventually learn their limits. They will recognize certain things as dangerous and off-limits to them.
So don’t be afraid to get creative and do some DIY child-proofing. It is often cheaper and more effective.