This is all a matter of one's predilections.
Traveling with one other guy, we played 13 courses (one twice) in 7 days in Northern Ireland and Ireland the last week of September 2008. It was the most fun I'd had since I played 12 courses (one twice) in 8 days in Scotland with two other guys in September 2005. I wouldn't have changed a thing. On both trips, we played courses both well known and lesser known, played with members and met locals (including, on the Ireland trip, GCAer Matthew Hunt), ate meals at the clubs and got to experience the variety of links golf that is unique to those countries. Some driving was involved, but it was very manageable. We never felt rushed. For me, the joy of new experiences trumps whatever additional knowledge I might gain from a second playing of a course, and I can see and learn a whole lot the first time round too. It's going to take a lot of additional playing before I truly know a course like Royal Dornoch, as much as I'd like to do that. Bottom line for me: We might never pass through these parts again. Let's experience as much as we can. If I ever get back there, I will know what I really like (eg, Royal Dornoch, Cruden Bay) or don't (eg Dornoch Struie, Lundin Links) and will plan accordingly. Others might do it differently, or think I'm nuts, but as long as I'm healthy enough to do it this way I plan to do so.