Sometimes I do, sometimes I don't.
I agree with Team Trout (and of course others, too!!). I seem to be gaining a reputation for caches that have been hidden in a very natural, thus difficult to find fashion. The funny part is that they are probably more well hidden now than when I established it!! I will be sure to continue to visit them regularly to ensure that the difficulty rating remains consistent with the way that it is hidden.
I typically try to cover the cache completely when I replace it, though if it is removed enough from a trail and unlikely to be seen by passers-by, I am less apt to be as diligent in my effort to do so. Plus, I am razzed regularly by people I cache with who believe that at least a small portion of the cache should be visible - LOL!!