I meet many guitar players (and musicians in general) who have been practicing for many years, but have yet to venture into recording themselves.
Through time I found that recording yourself is one of the greatest tools you can use to improve your playing. As the saying goes - The Recorder Never Lies. The recorder doesn't bend the truth. It plays back exactly what you played.
Listening back to your performances and being able to hear yourself "on tape" is extremely important. It is important because you can hear the things that you like or dislike about your playing. As a matter of fact, you can't come as close as you can to mastering your instrument unless you master the art of recording.
Hearing yourself back can be a tough exercise. Your flaws come back at you and stare you in the face. But, what a great chance to know exactly what you need to work on! Think of this as if you are looking into a mirror before you go out. Why do we do this? Simply, so we can some clues of what works or doesn't.
Side note: Ladies, metal guys have it easy. Pretty much any black T-shirt matches black jeans. Thank you very much. :-)
Are you getting my point?
My playing took another turn all together when I started to record myself. I started with cheap 4-track, moved onto a better 4-track like the one pictured, then an 8-track, a better 8-track and eventually into a studio quality computer based Pro-Tools system. I wore these things out. Working with an outside ear such as a producer also elevated your game. Objective opinions can be great.
Lastly, recording yourself will help you know how much you've improved on the guitar since it is hard to judge your progress from day to day. You can even use the tool of recording to tape your band rehearsals. Then, bypass the need to argue as everyone will hear the part they are not together on. Good luck!