information:extraction, quality:corruption, structural:expansion, stylistic:tone
Strings

Strings were first made of sheep gut (commonly known as catgut, which despite the name, did not come from cats), or simply gut, which was stretched, dried, and twisted. In the early years of the 20th century, strings were made of either gut or steel. Modern strings may be gut, solid steel, stranded steel, or various synthetic materials such as perlon, wound with various metals, and sometimes plated with silver. Most E strings are unwound, either plain or plated steel. Gut strings are not as common as they once were, but many performers use them to achieve a specific sound especially in historically informed performance of Baroque music. Strings have a limited lifetime. Eventually, when oil, dirt, corrosion, and rosin accumulate, the mass of the string can become uneven along its length. Apart from obvious things, such as the winding of a string coming undone from wear, players generally change a string when it no longer plays "true" (with good intonation on the harmonics), losing the desired tone, brilliance and intonation. String longevity depends on string quality and playing intensity.