How important are guitar strings when it comes to getting the sound you want? I’ve always thought it rather daft to own a nice guitar but leave it strung up with old dull strings. During my time working as a guitar tech I would get very frustrated with the customers who came in wanting their guitar set-up but not wanting me to put new strings on it. “The strings are only two or three months old” they would say. Or sometimes… “I only change the strings when they break”. It’s not so bad, if the person has religiously wiped down their guitar and strings every time they’ve played it, but more often than not the strings on the guitar are just plain gross.
Old strings just don’t sound as good. They don’t vibrate as evenly as new strings due to dirt, corrosion or pitting of the string, unevenness in the metal as the string is stretched out over time. This is usually first noticed as the string becomes less crisp sounding, the high frequencies are lost. eg. If you’re playing the open A string, the string will be vibrating at 440 Hz. Thats 440 vibrations per second and is called the fundamental frequency. But on a real musical instrument as opposed to a straight sine wave, you get harmonics that give the note it’s depth and character. The string is oscillating loudest 440 times per minute, but it is also vibrating with less amplitude at other frequencies. So mostly what you hear is the fundamental frequency, but the other frequencies, the harmonics, are what gives the life and color to the sound. As a string becomes older, dirtier and less flexible it is still able to vibrate happily close to its fundamental, but the very high frequency vibrations are disrupted. The string no longer sounds bright and sharp and clear, it sounds like it’s played through a low pass filter. It sounds dull, without life or definition.
Old strings with their dirt and corrosion can cause premature fret wear on your guitar. They are more gritty and abrasive than new strings so will wear away at the tops of your frets faster. Also, if you aren’t changing your strings often you don’t get a chance to give your guitar a proper clean and oil the fretboard.
You can make your strings last longer by washing and drying your hands before you play your guitar, using a string lubricant such as ‘Finger Ease’, and wiping your strings down after you play. Long life strings are more expensive but do last longer.
For steel string acoustic guitar, Elixir strings (in my humble opinion) don’t sound as good to begin with. The coating they have on them seems to dull the sound. My personal favorites are Dean Markley Alchemy’s, which sound amazing. A close second for me would have to be the Martin SP+ strings.
For electric guitar, I quite like Dean Markley Blue Steel’s. And not just because I’m a Zoolander fan! They are long lasting and very crisp and clear. They don’t seem to suit every guitar though. I find some of my guitars need a warmer sounding string and then I just go with Ernie Balls.
I have just put Blue Steel bass strings on my bass and I’m really pleased with those. I have a very cheap old bass that was a borderline case for being chucked out but the strings have given it new life.
Buying the cheapest strings available is fine if you’re going to change them often. Even though I use long life strings I still change them before recording or a gig because there’s nothing like the sound of fresh strings.
I’ve often heard it said that you should change your strings after every 20 hours of playing. This sounds like a good rule of thumb, but it can depend on what kind of playing you’re doing and how you look after your strings. So it is a good idea to just use your eyes and your ears to decide. Do my strings look manky? Are the unwound strings showing signs of pitting and corrosion? Do my strings sound less than fantastic? Is my intonation going out?
The strings on your guitar are the source of your sound. Keep in mind that horrid strings can make the best guitars sound awful. And, because I’m a girl I have to say it, old strings are gross and unhygienic and probably will give you tetanus if you spike yourself on them. 
