How often do I need to change my guitar strings?

The life of a guitar string passes through several stages as it ages. 1. Brand new strings are bright and responsive. Depending on the alloy of the string and the construction of your guitar, this may either be too bright or make your guitar sound it's best. 2. After a short period (a day to several weeks depending on how much you play) the strings will mellow out a little. They will continue to slowly become duller in sound...but still be acceptable to most players over the course of a few months. 3. The strings eventually become degraded enough that they sound totally dead. There is no sustain and the tone is dull. The underside of the strings have become deformed from stretching and rubbing on the frets, so they are no longer a consistent thickness. This makes them hard to tune because the pitch will vary. 4. The strings become rusty. Sometimes the winding can sever from fret-wear, causing a buzz. The strings are prone to breakage. There is no excuse for leaving strings on this long. The time a set of strings will last in each of the above stages is dependent on the alloy and how frequently you play. Recording artists will frequently change their strings before a session....or weekly for optimum sound. The average player will change their strings sometime in the second stage....every few weeks to a few months, depending on how often they play. Only complete noobs or casual players will leave their strings on longer. I have a few guitars that I leave the strings on, for 6 months or so because I don't play those particular guitars very often. Let your ear be your guide. Remember: a new set of strings is the single most effective (and cheapest) way to make your guitar sound better.

it depends on how you like the sound of new strings. I have had guitars that i change regularly, and guitars I do not because i like the sound of old strings more

Depends a lot on how often you play and how it sounds. I personally like the sound of bright new strings and change mine every month or so. I play about 10 hours a week including every Sunday morning in church. Before I started playing in church though I would change them every 3 or 4 months. If you're just learning to play and don't play in public you can probably go 6 months without changing them (or even longer if you want). It's really your choice and depends on how you like the sound of your guitar. You should change them eventually though (don't wait until one breaks necessarily) because they will get stretched and weakened over time (metal fatigue). If you have trouble keeping the guitar tuned or it starts sounding dull and lifeless, then it's probably a good time to change the strings.

Every 6 months min. I prefer 3-4. If I played more, even less. ATM, it's 1hr+ a day, sometimes up to 3 or more.

In theory you should change them every month as, even if you don't play, the fact that the strings are under tension causes them to degrade. In practise, you should be able to change them less often. If your strings don't sound good, don't play in tune, look tarnished, dirty or rusty, you've left it far too late!

You really shouldn't have to change them either till they snap or until the sound is very dull and the ones with metal on them are all dirty or rusty. Some players like the dull sound though. I haven't changed my acoustic strings since 2007 and it still doesn't sound as dull as my dad's guitar which he got way back in the 70s.