When I use many of the conditioners I recommend, my hair feels a little stiff and stringy when it first dries. By the time I braid up my hair and sleep in it, the next days my curls are soft and clumped. I actually know I've used enough when my hair looks a bit stringy when they first dry. To me it means that my curls will dry in a good firm clump, so it's fine.

If by the next day your hair still feels stiff, or there are white spots, it means you may have used too much, or there is an ingredient in there that may not be good (if you are using other conditioners I haven't recommended).

I find the stiffness usually is totally gone by the next day, and it's usually also all gone if I wear my hair down for a few more hours after it dries. If you are in a hurry to get rid of the stiffness (though I think it's best for your hair to have the curls stiff like this for a few hours to make sure your curls get nicely set in that crisp curl pattern), you could wet your hands and run it over your hair a few times (but never run your fingers through your hair). This should get rid of most of the stiffness, though your ends may get a bit fluffy because they didn't have that extra stiff time to set.

Here is a video showing how stringy my hair looks after it dries once I've combed and defined it: