All tomato plants need to be supported and pruned. Tomato plants that aren't given adequate support or pruning will topple over quickly and become a jungle of branches. Most importantly, though, without this care, they will not produce healthy, prolific fruit.
Growing tomatoes is easy as they thrive just about anywhere. To produce healthy and bountiful harvests, though, takes a little bit of persistence. Starting them off well goes a long way in producing the bumper crop you desire.