I recommend making sure you have the app, and when you get a photopass card, you can scan it with the app and see all the pictures on your phone. That way, if you lose a photopass card, you haven't lost the pictures. If multiple people in your group get cards, you can link them all.
It's also fun to see the pictures soon, and if a must-have picture like a castle shot doesn't turn out, you can try again!