Ash, to be fair, Nero's had his for a good few months and his pretty crazy on them to put it mildly!
However bushings will wear out on all brands, regardless of whether they are plastic or brass, I think its really important to check your stilts over at all bearing/bushing points at least once a month, this will pick up any damage early before you damage your frame. I will do a diagram showing what to check for when I get a few mins.
for example:
A set of bushings will cost you a couple of quid, but if you damage your frame you talking a lot more!
In kiola's case, he damaged the bushings on the hoof, but becuase he didnt notice it till it was too late, the hole where they sat was deformed and so he had to replace the who hoof peice... and becuase he has PowerSkips it set him back over £100 (im sure he will tell you exactly and the pictures I think are on the forum somewhere!)