I have never pruned my tomato plants but I know lots of people do. I usually have a pretty good harvest but maybe it would be even better if I pruned them. Out of the 18 different varieties that I am growing this year I don't have any determinate plants. I have found that most tomato varieties that I have grown, especially cherries, are indeterminate. I am growing 1 variety that is semi-determinate and I am curious to see how that one grows.