Always prune the suckers and all the laterals if you want the best fruiting. That is, unless they are cherry tomatoes, in which case just let them go wild.

You don’t want more than one growing tip if you want really great tomatoes.

Edit: Most of the advice here is just terrible. Do what is proven by the pros. Rigorous attention to pruning laterals is the right way to go. People who say not to prune have probably never pruned properly so think what they do is OK. You need to do it every week before the laterals get too large or it affects plant growth. Just pinch them out with you fingernails as soon as they appear. Ignore the other advice. Thank me later.