Yes it is possible to over-water. ;) Clearly some days you may very well have to water 2x a day depending on the size of the container and the weather. Sometimes maybe even more. But many times the plant may only need every toher day or even every 2 days. So it shouldn't be a fixed schedule whether the plant needs it or not.

Each time you are washing nutrients out of the container and they must be replaced. And keeping the roots constantly wet leads to root rot, blossom end rot of the fruit, blossom drop, and other problems. As a very general rule of thumb, tomatoes are much more tolerant of too little water than they are of too much water.

Use the 2 knuckle test often recommended on this forum. Finger stuck into the soil 2 knuckles deep and water only if the soil at that level is dry. You'll have much better results.

Dave

If you have an excellent free draining container soil than yes it can be hard to over water. But most containered soils are peat based and hold water very well. Thus over-watering can be done quite easily with these types of soils. I build my own containered soils that have only 1 part peat to 5 parts bark fines and 1 part perlite.

Damon