I think that fits just about any kind of learning experience. I'll have one or two month intervals where there's a noticeable difference in my dancing, and then all of a sudden, I feel like I've lost something.
For me, dancing is two steps forward, one step back all the time. One thing I like to do is after a long series of instruction and coaching in preparation for a comp, I'll take two weeks off completely, and do no dancing. I feel kind of fresh when I come back.