Hi Jeff... Well... Statistically (for me personally) Something breaks every 15-20 jobs... Normally it will be the belt & it will sustain minor wear damage during use... over time the steel strengthening inside will find its way outside of the belt & wrap itself around the mechanism there & get ripped out of the belt by the motor... if your lucky you can hear when this happens & stop the machine to sort it out... (i always carry a tool kit for my gear including a spare belt ready for this kind of thing).
if you catch it early, you can just remove the belt & snip the steel as close to the belt as poss & then replace it & maybe it will be ok again for a job or two...
The belts are now £17.95 + vat from Ashbys
(Im trying to find cheaper or better parts atm).
The Brush itself will last a bit longer... but the bearings inside will rust & cause the brush to move & rattle about... this movement will also help to destroy the belts quickly too... You will end up with a perfectly fine looking brush with a wobbly centre rod (too good to throw away) & then you will have to buy a replacement brush from Ashbys at £68.75 + vat
There is little you can do about either problem.... the only thing that i do do is i get a hypodermic syringe filled with grease & try to inject as much of it as i can in the little area around the steel rod & just hope that makes a difference...
However!!! I would Absolutely Not be without my Powerbrush as its Fantastic & i use it on every job i can