How often you change your guitar strings depends on many factors such as:

How bright or dull do you like them to sound?
How often do you play the guitar?
How do you take care of them?
How much money do you have?

STRINGS WILL START TO PLAY OUT OF TUNE AFTER MANY HOURS OF PLAYING TIME.

Here is a chart to follow providing that you wipe your guitar strings down after every time you play, you prefer that they sound fairly pure and alive, and you are not broke.

The condition of your guitar strings deteriorates because they are made of steel. The oils and dirt from your fingers build up on the them, sweat from your fingers play a big part. this causes corrosion which makes the strings sound dull. Humidity can also cause them to corrode. Even if you don't play at all, your guitar strings will deteriorate over time.

IF YOU GOT A DEPARTMENT STORE GUITAR, CHANGE THE FIRST SET IMMEDIATELY.

WHY,,,,???THEY COME WITH REALLY CHEAPLY MADE STRINGS THAT WILL NOT PLAY IN TUNE OR THE GAGE IS TOO HEAVY FOR MOST BEGINNERS.

MOST WORKING MUSICIANS PLAYING 2-4 NITES A WEEK WILL CHANGE ONCE A WEEK.

ERNIE BALL WONDER WIPES, FAST FRET, AND FINGER EASE ARE GOOD PRODUCTS TO KEEP IN YOUR CASE AND WILL PRO LONG STRING LIFE.

RONNIE OF THE ROCK BOTTOM BLUES BAND SAYS THE RUSTIER AND THE DEADER THE BETTER. HE ALSO QUOTES THAT SOME OF HIS GUITAR BUDDIES CHANGE AFTER EVERY GIG.