I'm a newbie but I've watched friends for years who play and here's what I've seen. I have a friend (I'll call him Bob) that loves guitar and probably has more raw talent than most of the people out there playing professionally but he's never progressed past a couple of failed attempts to start a band. Bob can play any song he hears and play it well, but he has no feel for writing music and putting it together from scratch, and he'll admit it. He also hasn't progressed in his playing skills in years, even though he plays several times a week. Another friend (Jeff) is like me, has a passion for music and guitar but the skills come slowly. He, however, has kept to a pretty ridged practice schedule for years and now he can play circles around Bob AND he knows and understands how the music he plays and writes is put together. He plays in a fairly popular local band, but he came into his skills pretty late. If he had started playing in his teens... who knows where he would be.

The point is that I think that electric circus is right, mostly. Everyone can benefit from some sort of structured practice schedule. Some of us need a tightly structured schedule (I do) and some not-so-much, but having goals and working toward them will get you farther than fooling around with no direction. Bob finally understands that now. He now sets aside practice time to work on specific things and he's progressing.

On the other side, all work and no play make Jack a dull boy. Leave some time in your practice schedule to shred and goof off. It's supposed to be fun too!

Just my two cents.