when one or more break as new string sound not everyone likes. if you have lots of cash and love the new string sound though when they start to sound boring.
Answer
When they: start to sound muffled, start to buzz, feel rough or the overwind (4 to 6) starts to unravel, kink or break freely.
When your strings begin to sound "dull".
It could be rust? Either way, you will want to change the strings. Sometimes the people at the guitar stores can change them for you if you dont know how.
take it to a guitar shop
Change out the strings with a lighter gauge. (Get thinner strings) ---Shawn
You don't! When the strings have become worn you throw away the guitar and buy a new one.
That depends on the guitar! On a Tenor guitar there are four strings, on a standard guitar there are six strings, and there are twelve strings on a twelve string guitar.
pitch
Not normally. You will get a variety of answers on this. In Rock it really doesn't matter. Replace a string when it breaks. No one will know the difference. With a classical guitar, the change in tone between new and old strings is more noticable. But I would not change the strings on a classical guitar until I broke one. Then I'd probably change them all. I have heard that some bands change the strings on the guitars before every gig. This is plain stupid.... just tying to be cool.
the tension on the strings are what gives each string the "tone"
there are six strings on a guitar
The harder you pluck the strings, the louder they get. You can change the pitch by using thick or thin strings
generally no if you take off guitar strings after they have been on there for a while and tuned they would have stretched so if you take them off they will lose there tension and you will have trouble tuning your guitar so its best just to clean your guitar when you need to change the strings