Young seedlings only require watering about once a week, any more than that will cause edema and root rot.
Potted tomatoes, in most climates, will require water at least once a day, maybe more if you live in an extremely hot or arid climate.
Tomatoes that are planted in the ground or in raised beds will require less watering since their roots can reach deeper into the soil for moisture. If your soil is covered or mulched in some way it will help in retaining moisture. You may be able to water every 3 days to once a month depending on the above conditions.