It depends on if you have determinate or indeterminate plants and where you are.
All gardening is local. Do you get summer rain? there may be no need to water the plants, in fact, here in California we get no summer rain and we usually water tomatoes once or twice a week. If they look limp in the morning then it is time to water. If they look limp in the afternoon, wait until morning to judge.
You can do the pencil test. Push a new, sharpened pencil into the ground six inches and when you pull it out what does it look like? If it appears wet or damp-mud or bits of soil on it-dont water. If it comes out bone dry, water. Check again in about four days to see if it is time to water again.
Out here the best tomatoes are dry irrigated-little or no additional water once they start to ripen especially if they are determinant..