I have a longer post waiting in the wings, but I just came across a beautiful Lee Konitz quote:
As soon as I hear myself play a melodic segment that I already know, I take the mouthpiece out. The art of improvising implies, from the first note onward, that the slate is clean. What interests me is the procedure that falls into place without premeditation. The important thing is to flee the task that's assigned to you.
I love that, particularly the paradoxical last sentence. When I read something like this, or when I hear Konitz play, I am filled with admiration. And I'm a little chagrined about my own playing. Konitz and Steve Lacy are two of my heroes, and they both exhibit the same pure esthetic in their playing. They are (or were, in Lacy's case) interested in improvising melody, not in creating excitement, not in working up the audience, and certainly not in running through predictable patterns. Lacy, unlike Konitz, sometimes ventured from melodic improvising into sound exploration, but he even did that his own way - no screaming, no "finger-wiggling," but an exploration of the saxophone's sound capabilities that was just as thoughtful as his melodic playing.
Not many players in jazz have maintained such a pure approach to improvising. There have been numerous published studies of Charlie Parker's music showing how he combined his favorite licks and devices in different ways time and time again. Parker, of course, was a genius, and his solos were so brilliantly constructed that his use of set material didn't weaken his incredible music. But we've all heard lesser players who keep coming back to the same licks. And Johnny Hodges was one of the most amazing saxophonists in the history of jazz, but he often used the same set solos every night for many tunes.
I certainly don't come close to the melodic purity of Konitz or Lacy. With the 4th Ward Afro-Klezmer Orchestra, I only get a few solos per night, and I often plan the opening phrase of a solo before I start to play. And I do resort to devices that I know will "work" - building my solo gradually to a high point, then tapering off fairly quickly, for example.
There are lots of ways to improvise, and few of us have the musical and personal strength to improvise the way Konitz does. But I've found that the closer I keep his example (as well as Lacy's), the stronger my own music is. I'll make sure to keep them close.