When is it Time to Move on to the Next Song?

One of the most common questions all guitar players ask themselves is,
“How do I know that I have this song down well enough to move on?”
On the flipside if you are working on a piece of music and is taking forever to learn, when is time to set it down and come back to it later?

When you should move on

If you can play it from memory along with the song or backing track at full tempo with only a handful of mistakes, then you are at the point where you can move on.  With that said, be sure to go back to it on a regular basis and review.  You'll be surprised at how much more comfortable you get with the piece and how better it will sound over time. 

When to give something a rest?
If you have been working on the same piece of music for several days and you are getting frustrated with it, it may be time to take a break from it and come back later. With that said, you need to do a gut check and not use this advice as a cop out.  Did you give it your all?  Did you dilegently work on the piece?  Its very possible that you picked a song that was outside of your current ability.  Thats ok.  It happens all the time.  Be sure you are working on material that is just barely outside of your current level of playing so that it provides a challenge and allows you to keep growing.

The key points here are to stay motivated, have fun and continue to grow in your guitar playing.