I've been playing rythym guitar for many years and have just started on some solo/lead guitar. I'm practicing scales and trying to learn more of the fingerboard, and I'm paying a lot of attention to my little finger and using it a lot when doing scales. But when I relax and start to improvise and jam, I change my fingering and rarely use my little finger. Should I be forcing myself to use my little finger more often? Where is the dividing line between the 'correct' fingering for scales and just doing what comes naturally? I notice that I might start a melody with the correct fingering, but as soon as I do a slide I abandon the correct position and fingering, and start using just three fingers again.
when using the pinky for scales, it is merely for reaching convenience so if you wanted to fret the 12th fret and then hammer-on to the 15th or 16th fret you should use your pinky.

however if you are moving alot up and down on your own improvised lead lick(s), you should be doing what feels more comfortable. basically if you are playing on the 12th fret and want to move to the 17th fret and it feels right to slide to the 15th fret first, then do that, don't force yourself to fret that with your pinky.

basically use your pinky when it is nessecary, and always use it when practicing scales or other people's licks that have large stretches to keep it strong enough to play with, but don't force yourself to use it on your own licks that don't require it.
Quote by Dirk Gently
Some pieces are only meant to be played by people with six fingers on their fretting hand. Sorry.
the reason you are naturally not using your pinky is because you never have had to use it before, and your brain is used to coordinating only three fingers. it is also therefore weakier than you other fingers becuase you havent used it so your brain is reluctant to use it. trust me when i say, force the habit of using pinky. i have had same problem, where my pinky was unused until recently, and it is tough now trying to coordinate it, and get it up to speed and accurate as my other fingers. i think force it now, benefit from it later. Scales are good exercises, there are tons of lessons on UG for this kind of thing. i find typing on keyboard helps too, hey im doing it now hope this helped abit
Work it trills are Allways good. When it burns shake it out and start again.
But this goes up to 11
Lots of very famous guitarists are "three finger" men... However, using ther pinkie properly is more efficient and working on it will improve your playing.
One exercise I found useful was out-of-position jumps played with the little finger. As in... If you're playing at the first position, jump over and play a note in time with the little finger at the seventh or ninth fret.
Increases strength and accuracy. (I think I saw the exercise in a Larry Coryell article.)
Theres so many chords that require the use of all 4 fingers, dont know how ya can play without it...
2010 Epiphone Dot
2010 Gibson Les Paul Studio Deluxe
2009 Taylor 110 acoustic
Oh I can play plenty of chords with it, as that's pretty well practiced by now, but for leads and licks I tend not to use it. I suppose it's one more tool to have available so I'll try and work it into solos a little more often