If the frets of your instrument are worn, a Fret dress may be required to achieve an optimum level of playability.
It is completely normal for frets to wear over time and develop low points from which strings can buzz and fail to ring out naturally.
As frets wear the tops become flat, bringing the front edge of the fret closer to the saddle of your guitar and shortening the length of the string when fretted.
This causes the notes to ring sharp, making it impossible to accurately tune and intonate the instrument.
A Fret dress will remedy this and get your instrument back in top working order, but if left untreated deep grooves can develop and eventually the affected frets will need to be replaced.
A heavy left hand technique will increase fret wear and a comfortably set up instrument can prolong the life of your frets by reducing the pressure needed to press the string to the fret.
Old and rusted strings act like sandpaper on frets and fingerboards so it is a good idea to change your strings regularly and wipe down your instrument after use.