Often I am called upon to make a repair where a little inspection on behalf of the player might save he/she some money. I have a list of things I check during a routine setup and if one item is out of tolerance then it might just be a TONE KILLER!! Above is an example of a pickup mounting bracket being too close to the strings. In this case the action was off as well and buzzing and lack of sustain were the primary complaints. In addition, the action was low but also I found the pickups to be too close to the strings! In order to fix this I had to determine the proper string height but this setting is tempered by the players desired string height. This is where things get a little sticky. See, the longer the guitar scale (25.5 inch - long) the more the strings will sag over the length of the guitar. The sagging strings oscillate (excellent presentation of string oscillation - click here) when strumming and could cause buzz without fretting a note. A thicker string will sag less than a thin string but most people want thin strings and zero buzzing. It's a nightmare for the luthier to remedy. There are more variables and I'll list those that effect buzzing, sag et all.
Not in order of importance or systemic analysis....
- Induced neck bow.
- String gauge.
- Fret height.
- String height above the frets.
- Nut slot depth.
- Strings not seated on bridge properly.
Over all, doing routine inspections of your instrument can save your tone. Check all contact points. Look for misaligned strings, dirty fret boards, and string properly seated in the nut. Most professional guitarist frequently change their strings. Strings come in sealed package for a reason. Moisture in the air and other environmental elements oxidize strings. Old strings will kill your tone. I would recommend at least once per month even if you are not using your guitar! If you are playing a show or many shows - then your frequency could become greater. Those who sweat or play often with soiled hands will need to change their strings more often than those of the opposite nature.
Properly maintaining your instrument will help insure a longer life for the instrument and beget years of fun and fulfillment.