It depends where you are, but elevators are usually fine and decks have rules.

For elevators: I’ve never seen a building with an official age or height restriction. The rule is “don’t let toddlers push buttons alone” — that’s common sense, not a posted limit. So kids can ride, but they should be supervised.

For outdoor decks (on cruise ships, hotels, apartment buildings): This varies. Many cruise lines have minimum age or height for open deck railings — think 42 inches or 5 years old, something like that. They want to make sure a kid can’t slip through or climb over. Check the specific place’s policy. In a private building, it’s usually up to the owners or HOA — but good luck finding a posted rule.

Your safest move: call ahead or read the fine print if it’s a cruise. Otherwise, keep a hand on the kid and don’t overthink it.