Strings were first made of sheep gut (commonly known as catgut), stretched, dried and twisted. Modern strings may be gut, solid steel, stranded steel, or various synthetic materials, wound with various metals.

Most E strings are unwound, either plain or gold-plated steel. Violinists often carry replacement strings with their instruments to have one available in case a string breaks. Strings have a limited lifetime; apart from obvious things, such as the winding of a string coming undone from wear, a player will generally change a string when it no longer plays "true," with a negative effect on intonation, or when it loses the desired tone.

The longevity of a string depends on how much and how intensely one plays. The E string, being the thinnest, tends to break or lose the desired tone more quickly than the others.