A little of both. Like someone else said, our first few cruises we tried to do everything we saw in the Capers and it dictated our days for us. Now the only must see thing that we plan around is the Marriage game.
We normally look at the capers when we get back to the room in the evening and see if there is anything we really want to do. If there is then we plan it, if not we just wing it.
Excursions are planned before we take a cruise, whether a ship excursion or doing our own thing we know what we are doing ahead of time.