You can leave dry food out all day for cats but we wouldn’t recommend doing it for wet food. For one, it can smell when it’s left out for a long time. Two, it can encourage neighbouring cats to come calling and it isn’t the most hygienic way to feed a cat. Some cats like to graze and eat little and often, others prefer regular mealtimes. If your cat prefers the latter, a wet food dispenser for cats is the way to go.