When should one change the strings on a guitar?

When to change your guitar strings depends on how often you play, how they sound, and how they look:

How often you play: If you play often, like two hours a day, you might want to change your strings every month. If you play less often, you might want to change them every two to three months. Another rule of thumb is to change them after every 100 hours of playing. However, how often you change your strings can vary from player to player. For example, some players might change the top strings more often than the bass strings.

How they sound: If your strings don't sound full or clear, or they don't hold their tuning, it's time to change them. However, if your strings look or feel dirty but still sound good, you can try cleaning them first.

How they look: If your strings look dirty, you might want to consider replacing them