...once we get past a certain age we are stuck with it.
Don't get too bogged down in the technical side of things and you will free to be creative!
Bigvyor, I appreciate the input but I have to respectfully disagree with you on these two points...first off, I don't think one is "stuck" with something just because they've been doing it for a long time...one of the most revolutionary discoveries in the field of neuroscience in recent years has been the discovery of neuroplasticity, which basically states that virtually any skill can be learned/unlearned due to the fact that the brain is in a constant state of flux and basically rewires itself completely every couple of weeks...this is why you're able to learn new skills in the first place and also why you can sometimes "forget" some things that you haven't used in a while - if the brain loses it's neural network for that particular skill it's gone, but since it can rewire itself you can still get it back fairly quickly.
Case in point: I've been doing martial arts for years. I used to practice a particular style and got very accustomed to those movements...later I switched to a different style, with very different movements and found it virtually impossible at first to execute them...but with deliberate and precise practice those movements now feel entirely natural, and I am able to blend them seamlessly with my "old" way of fighting and even improving it...learning the new movements was at first constrictive, but eventually allowed me to be even more versatile with my fighting technique. Based on this I am assuming (hopefully correctly) that mastering a different style of drawing while still practicing and retaining my old style will have a similar effect, which brings me to my second point...
...which is that while I agree that being free to be creative is definitely the most important thing and for sure the ultimate goal of anybody practicing any art, being fundamentally sound on the technical side is what will eventually give you that freedom. I play piano as well, and the goal there as well is to be as expressive as possible with the music you play, but that isn't possible without countless hours of practice with scales, arpeggios, chord exercises, etc...drawing's a little different in that it's more perceptual and less structured, but it still comes down to mastering the different ways you can use your tool to create different marks, and while tedious, doing exercises and practicing technique for the sake of it I'm sure must have some effect on how freely you can use that tool to express yourself in the long.
All that aside, what it really comes down to for me is...I never learned how to do good, fully rendered, chiaroscuro type drawings, and I really want to. So I bought a bunch of books on it and I'm going to do every exercise in everyone until I find a style/method that suits me. Hopefully I'll make some progress and will have some work to post soon