are a very important factor, when it comes to the sound and playing of your instrument. It is important to understand the kind of guitar you have. Acoustic, solid body, classical or folk. The type of guitar strings needed for the guitar you are playing. A classical guitar, falls under the acoustic guitar category, and must be strung with nylon strings. Where a flat top acoustic guitar will use steel strings. Giving it a more metallic sound. You can use Phosphor bronze or 80/20 bronze. And they come in a variety of gauges. The gauges you select are determined by the way you play and the sound you are looking for. And by the preference you choose. Solid body guitars need to be amplified, and use steel core strings. Nickel wound, pure nickel wound and flat wound. And again, come in a variety of gauges. The type of string you use is again a personal preference.