I am not sure perhaps it was always so but recently I used
D'Addario EJ45-3D Pro-Arte Nylon Classical Guitar Strings, Normal Tension
and all of my guitars string just in 1 month using it has become like this
What do they call this in Egnlish ?
I play 2 or 3 hours a day but distributed on 2 or 3 guitars I did not have this experience with other strings not too soon am I playing a lot recently?
And these strings are on for less than a month . Strange