WHY DOES A NEW GUITAR NEED A "SET-UP" ?

Someone brought a guitar in the other day. The guitar was uncomfortable to play. High action, buzzing in the centre of the fretboard. "Why?" the customer asked, "This guitar is brand new!" Every guitar should start it's life with a proper set-up, but not every new guitar is set to tolerances that the average guitarist would be happy with. Why? There are a few reasons....

Players have different needs and expectations from a guitar
There is no one adjustment that is universal - the string height at the nut, but to a degree, neck relief can vary from guitar to guitar, overall string height can vary from player to player, and string gauge is a personal thing, which affects every setting.....

The climate a guitar is stored in affects the overall set-up
Wood absorbs and releases moisture. Guitar necks and acoustic guitar bodies swell and shrink with fluctuations in humidity. This causes subtle and sometimes dramatic changes in string height and neck curvature. In the ideal scenario, a guitar is always in a place where the relative humidity is around 50% and the temperature is 24 degrees. In reality, this is rarely the case. While some guitar makers require their distributors to store and show guitars in a climate controlled room, in reality not all do. A guitar set to close tolerances is going to be affected by any changes in humidity and temperature.

Even a "new" guitar may have been sitting for a while before you bought it
Guitars "settle in" over time and often need adjustment for this reason alone....

Some new guitars don't need a complete set-up, just an adjustment
Many guitars come out of the factory with a good but not great set-up, this combined with climatic changes, or a change in string gauge compared to is factory-installed, may require some minor adjustments.