If the Fantasy Baseball is any guide, you can spend as little or as much time picking your team as you want. The key is to have at least 5-10 minutes a day at the computer just to make sure that all the guys on your team are all playing that day, and replacing any that aren't.

There are "salary cap" considerations, though. When you put a guy on your team, you have him forever at whatever "price" you paid for him. If you replace him, and then want him back later, his price may have gone up, and you can only get him back at the new, higher price.