Peter Zalocha, BSS Guitar Instructor
When should classical guitar strings be changed?
Nylon guitar strings are constantly under approximately 90lbs of tension when in tune. That, and daily practice can seem to wear the strings out rather quickly! Generally, bass strings wear out more quickly than treble strings, and it makes sense to purchase extra sets of bass strings. When I buy strings for the guitar I play every day, I try to buy an extra set of basses along with a full set; so I change them twice as much.
You know your strings need to be replaced when they start to lose their tone. In other words, they don’t sound as warm/rich as they used to; instead they have a flat or weak sound. Sometimes this can evade you, and soon strings get visibly in need of replacement (i.e. They look dirty, wear marks over frets, or worse case, the bass strings begin to unravel).
Good strings aren’t cheap, but it could be worse (bassists). I like to keep the strings fresh so I change them fairly frequently, which is tricky because there is a lot of stretching involved to get the strings to settle within reasonable proximity of standard tuning. This becomes an endless struggle trying to maintain optimal tone and tuning together. My general rule is that once the strings have settled, it’s time to replace them!