I've experienced the same thing with my son, and knowing that this tends to be what happens, I work with it. Right now, it's drawing and writing. For the longest time I would see kids his age coloring pictures with different and appropriate colors, at least trying to stay in the lines, and my kid? One crayon, three scribbles, "I'm all done," and he'd move onto something else. He just didn't seem to care about it. His abundant (abundant, did I mention abundant) inquisitiveness and communication skills showed me that I had nothing to worry about as far as overall development; he just didn't really care about drawing or coloring. Until about two or three weeks ago. All of a sudden he's coloring (mostly) within the lines, showing an amazing attention to detail where color is concerned, you can recognize his name when he writes it, and he is asking to practice drawing and writing, all on his own. Something just finally clicked.
How does this factor in for adults?
I know similar things have happened to me, as well. I'll struggle with something for a while, seem to be beating my head against the wall, and then all of a sudden, it clicks, and magic starts to happen.
The tricky part is finding the line between exhausting yourself working on something that just doesn't seem to go anywhere, and sitting there doing nothing while you're waiting for the time to be right. It's possible that continuing to work on something you're having a hard time with will eventually pay off and the work itself will make things click; it's possible that waiting for the right time will actually help you find it, and once it's right, things will magically fall into place. I also think it's possible that the right combination of both attitudes could yield some great results -- that putting the time in and learning what doesn't work could be an important step of letting things work perfectly (give or take) when the time is right.
I'm not sure if a child who had never used scissors before could know exactly how to use them at "the right time" without the prior experience, or that my son could color Robin (as in Batman) with a red suit, yellow buttons, a green mask and a yellow cape if he'd never before held a crayon. But even with some prior practice, they weren't able to do it well until they were ready.
So how about this: if you're beating your head against the wall over something, relax, and know that when the time is right it will pay off. Conversely, if you're hesitant to take any first steps until the time is right, start trying something until then just to get some practice.
What examples do you have of things working out well when it was obviously the right time for it to happen?