We go around 30 hours between kyu grades if you have the ability. Obviously sensei would try to dissuade someone if he thought they weren't ready. I feel more than read considering I missed my last 2 kyu grading through injury and other time off. I have to wait another 100 hours before I can do my Dan Grade after the 1 kyu though
This is one thing that has puzzled me about people taking a year or so between kyu grades. Is there a reason why some organisations/clubs/dojos test more sporadically than others?
Even for our 5th kyu test (first test in our dojo) you have to have at least 50. For our 4th kyu, you have to have about 90 or so (I have over 200). It goes up from there, but from 1st kyu to shodan, it is at least a year of training. Our dojo doesn't hold tests that often, so if you train regularly, you are going to have way more hours then you need by the time you test. I actually hate testing though, so I like this method myself.
Our dojo does have a general technique list that you need to demonstrate during a test, but we actually have two lists floating around.... and he can add or obmit things... so with us, its somewhat set in stone, but not.