I have a (most of) a set of Elixirs on an acoustic, which I have been using for more than a year. They have turned an unpleasant shade of green around the second and third frets, but do not suffer from buzz or any loss of tone.


I usually carry a set of cheap strings (various Ernie Balls, and whatever I can, ahem, acquire, at sessions), as emergency spares; I suspect that once Elixirs have worn out, they will have been worked absolutely to death, and there will be no point in keeping old Elixirs as spares.