Here are some ways you could translate it depending on the context:
* From time to time
* Occasionally
* Now and then
* Every now and then
* Once in a while
For example:
* Spanish: "Voy al cine de vez en cuando."
* English: "I go to the movies from time to time."
* Spanish: "De vez en cuando, me gusta salir a comer."
* English: "Occasionally, I like to go out to eat."