I water when I plant out, and maybe once or twice in the first 10 days. After that they're on their own.
So many people waste so much time and water giving everything a daily sprinkle, which damps the surface and nothing else. If you're going to water, please go back 12 to 24hrs later and scratch down 4 or 6 inches and see if the water got down there. If it didn't then you've down nothing for the long-term growth of the plant.
There will be some, very sandy soils which may require a soak every 4 or 5 days, but for most it's just not needed.