As well as you try to prepare, you can never be prepared enough. I like to think that I'm a pretty well prepared person. Before I went abroad, I tried ensure my own graduation safety. I made sure that I finished my freshman to junior courses all in my first two years. That way, when I went abroad, I wouldn't have to worry about getting credits for my major. I thought that that kind of preparation would be a worst case scenario. Thank goodness I did though, because that was just what happened. I was unable to take a single course towards my major. One of the issues upon returning from abroad is unit conversion. As you know, eight of the UCs are on a quarter system. Thus, the Educational Abroad System uses a quarter unit system. These quarter units are converted to semester units for Berkeley (and I suppose Merced). If the school abroad you are at is a quarter system, then you mostly don't have any complaints. The issue comes in when the school abroad is a semester system. Instead of direct semester to semester transfer, it is from semester to quarter to semester units transfer. For example. I'm taking a 2 unit Organic Chemistry I class here. This becomes 2.5 quarter UC units. This will finally become a 1.6 semester Berkeley units. That missing 0.4 units is a painful thing and can often mean the difference between a course being accepted as equivalent and not.
Another issue is the course schedule. Before coming, I had planned on taking a dozen or so courses in international studies, humanities, and Japanese. Yet, all Japanese courses are 2nd and 3rd period every day of the week. Most of the classes I was interested in fell into 2nd and 3rd period. Unlike Berkeley where one may sign up for time conflict classes, you may not do so at ICU, nor is there any way to override the system.
Thus, while I enjoy studying abroad, don't expect to get any major or requirements done while abroad. The only thing you may be able to get fulfilled are your breadths, and you may not even be able to do that unless you have advanced level Japanese. If you have beginner to low intermediate level language skills, the course and scheduling restrictions will keep you from doing so.
But note, I would still study abroad again if I had to do it all over. The experiences you gain here are worth more than the difficulty in getting credits.
