guitar strings ?

They have to be changed if you want to have the best sound possible from the guitar strings that they can get.  You don't have to change them, only change them if youre not hearing the results that you like.  I mean you don't have to tune your guitar either, you can go off on some experimental plonking thing and as long as you like it till they are all broken.

In general though, the reason we change them is to give it the best sound we can.  Strings get dirty and dull and sometimes break, and when one's bad, the others are probably not far, so we tend to change them all at once so you dont have 1 bright dtring with 5 dull sounding ones.

Instructor

Get a string cleaner like Fast Fret or Kyser string cleaner and give them a wipe down after each session and they'll last significantly longer. I tend to leave my strings on a fair amount of time but with a bit of experience you will hear it when they lose tone and elasticity. If you want that new string snap all of the time then you would need to change strings fairly regularly. Once you get tired of forking out for new sets you'll probably put up with a duller but still playable sound.

Strings are meant to be replaced in 2-3 years. How old is the guitar that yoiu just bought off the pawn shop? If its old enough (like 5-6 years) and is a Holmer, keep it safe and restore it. The Wood gets matured enough then you sell it off for some 500-600 pounds!

I used to change mine all the time, I have just started putting on rotosound yellows and I really like them.

Ive found D`Adarrio strings to be virtually indestructible and are good intonation for ( true note )They do accoustic and electric.About £6.50 a set for electric...acc are dearer.