Cleaned my stepper way back in January. Seemed OK, but got a new one anyway. Finally got round to changing it today. Took exactly 15 mins start to finish. Would have took 14 if I hadn't cracked my head on the underside of the bonnet, and spent a minute running about and swearing a lot.
I'm amazed at how much better its running now. Who would have thought such a little part, would have such a big impact? (over to you Bernard...!)