Split barrel adjuster

joncomelately

Evening all. Just polling collective experience; the trusty commuter with a 105 rear derailleur wasn't shifting spot on today, so went to twiddle the barrel adjuster and found the plastic bit was split around the outer. An easy enough fix once I can pick up a replacement, but is this a common failure? Anything I can do to avoid it? The mech is only about a year/1500miles old... TIA