It all depends on what level you are compeating at.
The Levels go from lowest to highest:
Beginner Novice max fences 2'7"
Novice max fences 2'11"
Training max fences 3'3"
Preliminary max fences 3'7"
Intermediate max fences 3'11"
Advanced max fences 4'1"/4'3"ish
and then you hit Professional
1*
2*
3*
4* is Olympic and Rolex Level.
Most courses in Michigan offer levels from Beginner Novice to Training. Then when you get to Prelim and bigger, there are a few courses in Michigan that offer these levels. Most riders at those levels go out of state to compeate at bigger, rated USEA courses.
So when you see vids like mine, those courses are set from BN, N to T. So the smaller fences, are for BN, the medium fences are for N and the bigger fences out of the 3, are for T.
The course is organized and set up before the comp happens, where each fence is marked and labled. The course is marked out on a map for all riders who are compeating, so that when you walk the course the day before the comp, you'll know where your going and what fences you are riding. Most Eventers walk the course 3 to 4 times. If you jump a fence that is not yours, you get eliminated.
Beginner Novice to Novice, the fences are strait forward and basic. Basic striding, basic rhythm, nothing too technical. The point is to welcome you to the sport, and to teach you the basics so that when you climb the ladder of levels, you are prepared. Most of the fences are just point and shoot. There is NOTHING technical at lower levels, not until you get Prelim.
When you get to Training, that's when combinations arise and that's when drops appear and tougher terrain appears...but not so rough.
Preliminary is when things are alot tougher and so on and so on.
The jump from BN to N isn't that difficult. And the jump from N to T isn't either - BUT the jump from T to P, is!
There are no "option" fences either at lower levels, you jump what is put infront of you. If you cannot, you are eliminated. Reason being is, if you can't do what is there for low levels, you have no business moving up.