If your guitar is not in tune it is not going to sound good. Every time you pick up your guitar and after you finish playing, it is good to tune your guitar. It will help train your ear to hear each note and is a good habit to get into.
Even if your guitar hasn’t been touched in a while, it may have gone out of tune due to a change in temperature as the neck of your guitar is made from wood, which contracts and expands in warm or cold temperatures. This affects your guitar’s tuning. Your guitar can also go out of tune when traveling as it might move around in transit.
String bending will increase the tension behind the nut and stretch the string. This can make your notes either sharp or flat.
