I would say go for 4 if it is possible. We actually do 6 days. We live in Utah which really isn't that far away, but we don't get to DL as much as we would like to. So when we do go, we make sure we have enough time to do everything we want to do, several times. We are people who like to take our time, though. I have read all of the "battle plans" some people have for DL, and while I really admire those people for being so organized and taking so much time to figure out the best way to see/do everything, we would rather just go with the flow and hit whatever ride sounds good at the time. We also use day 6 as a shopping day. It is just a half day as we fly home that afternoon. We look through all of the shops throughout the first 5 days, and then on day 6 we go buy the things that we decided we really want. This works really well for us.