On the durability scale it goes from “Consumer” to “Commercial” to “Industrial” and then finally to “Children’s Museum”.
While most adults can figured out how things work, and most will actually use things the way they are designed to work, children will use things every way possible, not (usually) maliciously, but because the are still figuring things out. Install a lever that goes up and down, and they’ll move it up and down with all the force their small bodies can muster, so you might want to add some hard stops on the inside.
Kids also can’t read/don’t read (to be fair, many adults don’t read either) so add some arrows showing direction of movement. Also if those arrows are just vinyl you applied to the surface, they’ll get peeled off. Every interaction needs to be thought about in great detail, and sometimes you need to think like an angry vandal hell-bent on destroying things.
Plan for things to break, because they will, but make them easy to maintain and repair. Use off-the-shelf parts when you can, so replacements are easy, or if you fabricate the parts yourself, make spares, and document how to make more spares in the future. Use Loctite. Use set screws. Use Loctite on set screws. Use hot glue. Use lots of hot glue. Use screws and bolts, not nails and staples. Make sure you can take it apart and repair it.
Stay Durable, Friends!