If referring to HUD / Database software, i would say although they are not 100% necessary to become a winning player, alot of players consider it to be a huge advantage. The real time HUD stats, whilst shouldn't be used solely to make our decisions, can definitely store a lot of info that you would more than likely have forgotten by the time it comes for you to use that information against them. I use Poker Tracker 4 and thoroughly recommend trying their 30 day free trial.