Very little or a ton based on what you want to do. Basically you set up a team and a bench based on who you choose in the draft(draft takes about 1 hr.) then you devote a few mins. each week to adjust your team based on who your players are facing, wether they have a buy week and what the best match-ups would be vs your opponents team. This can be done pretty quickly, but you can also delve into the numbers and take some time with it. I usually spend no more than a half hour a week on it unless I am trying to wiggle a trade. I have also had great luck with the mobile app.