While it can be fun to take the whole family on vacation, it can also be quite stressful. There might come a time when you and your partner just want a bit of free time to yourself. If that happens, just know that most cruise ships come equipped with a daycare that's usually completely free. The cruise lines know that parents might want to go out to dinner by themselves one night, and they don't want anyone simply leaving kids alone in the cabins.
However, it's always a good idea to check ahead as some companies, such as Carnival, offer different services at different times, depending on a child's age. For example, their daycare for kids under two years of age has specific operating times.