I received my guitar a few years ago and haven't changed the strings. I don't know when the previous owner had last changed the strings, but it seemed as though it had just been sitting around for a while. I don't think I need new strings, but some people are appalled that I'm not changing them every few months. Should I change them or not? And if so, what is the best way to do that?
How often you should change guitar strings depends on how often you play, the chemistry of the oils in your fingers, and your personal preferences for budget, comfort, and tone.
I like to put new strings on a guitar after about a month of play, assuming about two hours of playing time a day. I have a personal preference for newer strings that sound new and feel new, and I'm willing to pay for strings more frequently than some other people. I also like to put on a new set before a gig and before recording, no matter how old the old set is.
You should be able to find plenty of guides on changing strings online. It is something that takes some learning and practice, like tuning a guitar. I find it to be a labor of love and I like to clean my guitar and check and adjust lots of little things on it.
It sounds like in your situation you should definitely get new strings, and to make the first string change easy and also make sure the guitar is as playable as possible, I suggest you take your guitar to a store and ask for a setup. They will need to keep it for a few days, most likely, but they will put new strings on it and adjust several things to make it as comfortable to play as possible.
I too haven't changed the strings on any of my guitars for years. They may not sound as good as newer strings would, but they're still perfectly playable - I'm not doing any paid-for recording or gigging work so I don't see a problem. On bass, many people even prefer the sounds of older, deader strings - some bassists simply never change them, and it wouldn't be wrong if you wanted to take that approach on guitar!
On the other hand, if you're wondering, why not do it once - you'll then be able to tell if it yields benefits.
How to do it depends very much on the type of guitar - try to find a youtube tutorial for one that is like yours.
Generally speaking, yes, you should change those strings. One of the big reasons to change your strings somewhat frequently is tone. The tone, or sonic quality, of your instrument depends on several factors, including your strings.
Newer strings have a brighter tone and tend to have more clarity. Part of the change in tone as strings age has to do with their design and tendency to wear out. As you play your guitar, the strings are being pressed against the frets and getting worn on that side but not the top side (where your fingers touch), which creates an inconsistency in the string, which will be uneven across the string, as some frets tend to be played more than others and parts of the string will never touch a fret. You will also have wear from picking the strings, which will also be inconsistent since you never really pick the underside of the string and don't pick on the whole length of the string.
Wrapped strings (the lower pitch strings) have grooves in them because of the wrap. As you play, the dead skin on your fingers will come off and get stuck in the grooves of the string, along with any other sort of dust in the air. This can eventually fill in the grooves of the commonly played parts of the strings and affect the tone. This is kind of disgusting to really think about, so that in itself (as well as my next point) may be reason to change the strings for some people, though you can also clean your strings with some retail products.
The oils naturally produced by your skin will also build up on the strings and this oil is known to break down the material the strings are made of, affecting tonal quality.
Aside from impacting the tone the strings will generate, this will also weaken the strings, making them more prone to breaking. From the wording of your question, I assume you are more of a casual player, likely in the beginner stages of learning. Lots of people play less aggressively earlier in their learning and when playing by themselves (as opposed to with a band), so if my assumption is correct, this likely isn't a major concern for you currently.
Part of how this all works has to do with the construction of the strings. All strings will have a structure about them that is designed to be consistent across the string, which allows for consistency of vibration. This will impact how well the strings produce and maintain a pitch and its tone. As strings age, they lose this consistency and will affect the tone, as well as the sustain of the string (how long the string will continue to vibrate and produce an audible sound).
The only real reason to keep an old set of strings is because you like the tone of those strings worn in that way. I've heard of a lot of bass players that do this, including a friend of mine that let me play his but casually threatened me if they were broken (I play kind of aggressively). I've even heard of bass players boiling their strings to remove all the built up skin/dust/oil so that they can continue to use the strings longer. While this can apply to guitar, I've never heard of anyone doing it. The change as the strings wear out makes the tone warmer/less bright and reduces the sustain. Since guitars are often used to sustain chords, the lack of sustain is usually not desired, and the reduction in brightness will give less presence, ie, the sound of the guitar wouldn't be as clear and wouldn't be as audible/present when mixed with other instruments.
Standard practice for guitar players is to change their strings several times a year and for those that play more, it could be as frequent as weekly (or more for touring musicians in particular). I think the average casual player would be well served to change strings a few times a year or as you get used to the differences in tone/sustain as it wears, you could change them as frequently as the change in tone/sustain is bothersome. I think it is very likely that once you change to the new strings, you will like the sound much better and probably want to change them at least a couple times a year.
Whilst endorsing what Todd says, if yours is a nylon strung guitar, then it's not so important. At least for the top 3, which should be a simple nylon filament, that a good rub over (and under!) with a lint free cloth will keep clean. The wound ones could do with a change, though, as dirt, grease and acid from your sweat will have infiltrated, dulling the sound. If it IS nylon strung, then simply study how each string has been attached at the bridge end, and replicate. At the other end, make sure you wind new strings on, so that each three are wound the same way. Without seeing the guitar, this can't be much advised on.
If they're steel, there may well be rust underneath - run a finger up and down the strings. If so, DEFINITELY change them. AND - clean them after each time you play!!
You don't mention whether you have a steel string acoustic, a nylon string acoustic or an electric guitar.
I'm a semi-pro playing several times a month. I have high acidity in my skin oil so guitar strings corrode quickly under use. I change my entire set of strings on a steel string acoustic or on an electric when I either break a string or when the string will no longer stay in tune. Some folks like the brighter sound of new strings. I don't mind the sound of older strings.
When I was younger I strummed the guitar hard and so I would change strings before every gig so I wouldn't break a string during a performance. I have a lighter touch now and let the sound system do the work.
I don't play a nylon string guitar.
Wow. Answers all over the map. I would say "If it ain't broke, don't fix it"
FWIW, I have a modest Fender Strat that I hack around on maybe 30 minutes a day four days a week and I have had the same strings for at least a couple of years and they are fine for me.
I did notice in years past that strings degraded and when I was first learning to play for some reason I went through a lot of strings because they would break.
I don't know if it is peculiar to this guitar or not, but the Fender practically never needs tuning beyond the occasional tiny nudge on the B or E string.
When I have changed the strings, I change the whole set and I use decent ones. It has been a while, but if I recall correctly, the last set was actually put on by the luthier I had set up the guitar for me. The difference in sound and play of the guitar was pretty dramatic before/after professional setup.
You should go with your own instinct. If you can't tell there is a problem and your ear is OK for pitch, I would say stick with what you have until there is a noticeable issue or you want to see if new strings improve it.