When the only way you know how to play “Amazing Grace” is in G, and your singer can only sing it in C, a capo will save your life (and your marriage if the singer happens to be your spouse). In fact, with a good capo you can play everything in G-based chords even when the rest of the band and singers are performing in whatever key they want. All you need to do is move the capo up or down the guitar’s neck to match the key. This is the guitarist’s best-kept secret and it just cost you nothing! When choosing a capo for your guitar look for ease of use, fit, and how it attaches to your neck.