Good advice.
Just to add something to that... after a few years you'll start to notice that the so called 'fast' leads or scales you were trying to play actually sound slow. That's a good time for you to start moving away from playing everything in 'scale' mode and actually creating and improvising well constructed leads of your own. You should be aiming at a point where you don't have to ask the pointless questions all beginner guitarists seem to ask...

"what scales should I play with what chords".
"what modes would sound good over this song"
etc etc..

... and instead, using your stored up knowledge of scales and modes from the last few years to come up with well constructed and melodic guitar solos instead of just going for patterns and extra speed.

If you're really desperate to get your speed up, you should look into putting together a basic MIDI system for your computer.. or if you can stand the cheeziness, get Band-in-a-Box. Playing to an actual piece of music is a lot better than sitting around with a boring metronome.