A guitar tuner is a device that helps a guitarist tune their guitar. They come in many shapes and styles and which one you use or choose to use should be something you talk with you Guitar teacher about.
The answer on “should you use one” is YES! Although it’s not necessary to have a tuner to properly tune a guitar it doesn’t hurt to use one. As it relates to the guitar student, a tuner can help support learning how to tune and build confidence in knowing what in-tune guitar playing sounds like. For professional guitarist playing with others a tuner insures that theirs guitar will share the same pitch as all the other instruments on stage (assuming that all the other instruments are using a tuner as well:)
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