Hi Chloesmommi -
I guess its really up to the individual, factoring in how quickly you tour, etc. We are two adults with no kids, so we move pretty quickly and only take 1 break in the middle of the day. If you had kids, etc. I imagine you would need more breaks. We go to DL 2-3 times a year so we know what we like to see, etc. So, the 3 day hopper works for us. I would definetly call DL and check about upgrading. That would be the best solution, buy a 3 day then if you find you need a 4 day, you can upgrade.
Also, I can't confirm this, but I've recently read that the hoppers expiration has changed. They used to expire within 14 days of your first use, but now they don't expire for up to 2 years. If this is true, then get the 4 day hopper and if you don't use one day you can use it again in the future.
Good luck!
Susan